used this only to find out that you cant place anything on top of it.......

im using this with Diurnal Dynamics to have permanent night + full darkness and was hopping this was a tile
and it seems its just a lamp in the form of a tile so its kinda useless

You're right: it's not a tile, but a lamp, so it will emit light when it's dark or when it's controlled via circuit network. Even if you can't build anything on top of it, it's not useless: Compared with regular lamps, it can't be damaged/destroyed by vehicles colliding with it, so you can drive around in your base without worry. Sorry if that isn't what you expected. :-)

its not what i expected indeed but the 2x2 lights do help a ton for having a bigger light source