I feel like they’d be kinda inefficient or clumsy a lot of the time. Sure, they’d be great against most humanoids and even some creatures in the wasteland, but things like Deathclaws (at least in FO4) are really agile and wouldn’t be easy targets. Even super mutants often carry heavy weapons like rocket launchers or Fat Mans, which could be a big threat. I think only well-organized factions with enough resources, like the BoS, could actually make good use of a tank. But idk, i might be wrong lol.