Why not? There is no word from Epic that unreal is only for big games. They even did “tiny” bloated examples.
Yes its very frustrating that i need to count every mb in textures while unreal wastes 100mb on start. (did not know its that much).
But give them some time, and pick best engine for you, they fail they lose some part of mobile market. But i hope they give some attention to sizes for mobile.