Lightmap at arbitrary resolutions?

This may seam to be a sacrilege to seasoned game-designers, but what are the side effects of using non ^2 sizes for “Overridden Light Map Res” ? Like 278 or 632?
You can set it so it can’t be really catastrophic? I’m not far away from starting writing a tool to set the Lightmap size per object based on surface area because I’m fed of setting 500+ objects by hand. Unity has automatic uniform lightmap-sizes with it’s GPU calculated lightmaps (take Note Epic, spreading into industrial/architecture/design visualisation means to make artists/architects life easier not stubbornly stick to old stigmas) and I must admit to my Unity collogues (the guys I make fun of everyday for their misfortune having to use Unity instead of Unreal) that this feature is pretty cool and lead to very consistent looking lightning.
So, does it blend?