the eVinci is designed to only produce 5 megawatts, and the Kaleidos is limited to just 1.2 megawatts of electrical power output.

Why would you even develop nuclear with such low output. There is no way people are going to be OK with casually moving these trailers (e.g. to a datacentre). If you're using nuclear, you might as well go big and develop gigawatts of power.

I guess the idea is to stack them up together to get required power. While at the same time they are safer and cheaper.

With that in mind, the DoE hopes microreactors could be used to power small, remote sites, with an eVinci described as a possible power source for a remote datacenter. The Radiant Kaleidos, meanwhile, is described as an alternative to a diesel generator, being a similar tractor-trailer-mounted size while being able to operate for five years without needing refueling.

Alternative to diesel generator does not inspire confidence.

I support nuclear power, but not litering the landscape with random small scale reactors that may or may not be well contained.

Boats, isolated research stations (arctic), under water, any place where it's hard to get to but you need electrical service.