Hydride tanks don't require those high pressures. Other than nuclear arms treaties, is there a technical reason they don't use those instead?
https://www.fuelcellstore.com/hydrogen-equipment/hydrogen-st...
In the Toyota Mirai, for example, the tank is located under the passenger's seats, in a nice little 'braced' area. Likely chosen because it's the least likely location for the tank to get damaged in a collision. Also the challenge of either having to 'choose' between a 'swap' tank and a 'fill' tank, or a more complex tank that does both.
I don't know. I haven't done a lot of research since it will be at least another decade until a decent vehicle suiting my criteria comes out (electric or hydrogen). No point in me even looking at it now.