I bought a bunch of eneloop pro, but using them in connected thermostats is always displaying “low battery” even after just fully charged. This is when I discovered that they are actually 1.2V

It really came as a surprise, is there a catch? Are they only good for low power stuff like remote controls?

Edit: it seems they do exist in lithium. Question remains why are the NiMH only 1.2v and why are they the most widespread?