FCEV (fuel-cell electric vehicles) and BEV (battery-electric vehicles) are a tradeoff. I found [0] from an FCEV proponent to be really interesting (it's hard to find any comparisons that aren't obviously biased, if anyone can suggest one, I'd like to read it).

I have quickly glance through it, but some of the assumptions seem to be pretty wrong. If I look in Fig. 4, at a range of 300 miles, this is what the Tesla Model 3 offers. The Model 3 is about 1800-1900kg, so much less than shown in the graphic, and the only FCEV in that range, the Mirai, is even heavier than the Tesla at the same range. So the weight for the FCEV is just plain wrong. And yes, the pure hydrogen tank is much lighter than a battery, but you have to add the weight of the fuel cell and the buffer battery as well as a lot of piping towards it. While hydrogen certainly has the edge in for much larger storage capacities, I can't see an advantage for car sized tanks. Said Mirai also has the same range as a Model 3. Not mentioned is the space requirement: a Mirai has less interior space than a Model 3, because the Tanks have quite a volume and have to by cylindrical shaped. A battery can basically have any shape desired.

My overall feeling is that BEVs and FCEVs will _both_ be used in the future. BEVs have some compelling advantages for short-distance travel like intercity commuting (like being able to charge them at home) while FCEVs have compelling advantages for long-distance travel, like higher range and efficiency and faster refueling.

With the current state of technology, I don't see any disadvantage for BEV. Recharging on the road is much less frequent than refueling of a FCEV, because you can charge a BEV at any outlet. Especially when parking over night. Considering that, the recharge time at a fast charge is only mildly slower, Hyundai ist at 18 minutes already. The quoted fast refuel times assume that the fuel station has full pressure, which might not be the case if another car just refueld there. And why should a FCEV be any more efficient than a BEV? Currently, assuming it would use "green" hydrogen, it takes about 3-4x as much eletricity.

that generator -> wheel efficiency for FCEVs is lower. While this is true, it stops just short of the metric we really care about: generator -> miles driven efficiency.

Sorry, what should be the difference between those terms?

A BEV has to spend a lot of its stored energy just moving its batteries around, while an FCEV uses a relatively light cylinder, so when you look at efficiency in terms of W/miles driven, the reduced weight of an FCEV can render it overall more efficient than a BEV.

No, the weight of the car has only a neglible contribution to the energy used for driving. For driving at constat speed anyway not - at highway speeds the air resistance is the major facter. Only when in a stop-and-go situation, the weight makes a difference, but there the recuperation of the BEV gets back a lot of the energy.

And in practical terms: the Mirai weights more than the Model 3, where is even the possibility for a gain there? And the almost-obese EQS from Mercedes seems to be more efficient than the Model 3 even thanks to a really low air-resistance. Ironically, its larger size does help with air resistance.

FCEVs are also a relatively young technology compared to batteries, so there's likely to be some substantial efficiency improvements still on the table.

Some for sure. But the big problem is for example the energy used to compress the hydrogen. This is plain physics, how much energy you have to spend to compress a gas. And currently, FCEV use about 3x as much energy as comparable electric cars, I don't see where they should catch up with that.