That truly depends on the way you want your bike seat to be. If you want to get the most comfort, you can consider having an armrest or a backrest with your seat. That's going to help you in that case without any doubt. But you should know that those are sold separately most of the time. That's why you should see if you want to spend a bit more to get these parts individually. That falls down to a question if you truly need them. So, if you need it, you can go for it. But if not, you don't have to waste your money on it.