I have only played this game for 50 hours or so, and have yet to reach middle game, so what I write will be biased likewise. I'm sure others will be talking about the system and how it's a mix of an open world RPG and a gacha game.

1. For the money aspect, I did not spend a single cent in the game (nor do I plan to). Yet the experience has been wonderful so far. Yes, if you spend thousands of dollars every month on this, you'll be able to get the latest and greatest characters. But for a free-to-play player like me, I need to plan out the way I spend the gacha currency called "primogems" very wisely. The game gives you quite some primogems when a new area and new quests are released and you play through that content (we've had 3 areas so far in 1 year including the one at the beginning), and after that you get a limited amount regularly by doing daily quests and so on. Usually a free-to-play player can save up enough to get 90 pulls in a couple of months or so? Therefore, advance planning is needed. I enjoy planning like that so I like it.

2. About progression: I feel it doesn't matter whether you're F2P or a paying player. Because, the whole grinding system is gated behind a system called the "resin", which is a thing that replenishes to full in about 24 hours, and it's the same regardless of how far you are into the game. And if I'm not wrong, EDIT: as someone below pointed out, you can buy resin with money, but the exchange rate of the amount spent becomes awful very very quickly. That means, as you go to end game, either you'll run out of things to do, or you won't have enough resin to accomplish all you want to do. At that point, it'll be more like: log in, do the dailies that take 20 minutes, kill some bosses using raisin for another 20, and some other stuff and you're done. That is, once you've cleared ALL the story and world quests, and that'll take atleast a few hundred hours in my honest opinion.

3. For pay2win: I don't think it's a pay2win game. There are some units that the game gives you for free, and once you reach a certain level called Adventure Rank, you get to participate in events that give free 4*s. Some of the units are really really strong even in end-game (Xiangling comes to mind). Besides, even if you don't have the "best" team for a given character, there are characters you can substitute in. It just depends on how brain-dead you want to be when choosing your team builds and actually attacking the monsters (my favorite example for this is: https://www.youtube.com/watch?v=UTrRZEZ0wO4 where the guy literally takes the free characters the game gives out, and uses the game system, skills, and so on to beat abyss 3, which is quite hard for a beginner. I was able to clear this stage at the early game thanks to this person's proof that it's possible to actually clear content even with starting characters.)

That out of the way, here's what I love about the game:

1. The story. I am a sucker for great stories, and Genshin is done quite well. I actually decided to start with a new account after sinking dozens of hours into an old one because I went through the story too fast (one chapter in a week). This time, I've decided to take my time and enjoy the story like fine-aged wine.

2. The graphics. The graphics in this game are of an extremely high quality when it comes to non-physical rendering (NPR). If you're somewhat acquainted with anime-style toon shading, this game does it very well. No, it doesn't look like a cinematic Hollywood movie, and it's not meant to look like one. But its art style might be the best I've seen so far when it comes to NPR.

3. Maybe a bit niche, but the Japanese voice acting is top-notch. MiHoYo have good taste when it comes to choice of voice actors/actresses. Note I don't know anything about the English/Korean/Chinese ones.

Lastly, I'll just rant a bit about how I feel when I hear people say "there's nothing to do in this game". Sorry for sounding rude, but no game has infinite content for anyone to consume; this isn't Netflix binge-watching. To me, the best way to consume this game is slowly and steadily. Think of it as dining a full-course meal at a nice restaurant with a nice atmosphere. Of course it's different from gobbling down a Big Mac at McD's and washing it down with Cola. You slowly take bites of each food that is served, a sip of the drinks that are served, and relish the taste. I feel that's the best way to get maximum enjoyment out of this game. Come back home after a long day and unwind with it for an hour or two, and then put it away for the next day. It'll easily last a few months, and the game's updated every 6 weeks with new content with small events in-between.

TL;DR: This is a fantastic hybrid of single-player open-world RPG and a gacha game with fantastic graphics and story that I feel would be best enjoyed slowly. If you have the chance to, I highly recommend to try it.