I think that the only reason to colonize planets like these is to place databanks on them. think about it how many people see a sparse and look at the structures on it this could be the only reason to place structures on one of these planets.

good reasoning, I take crappy planets for the green badges .

Taking crappy planets is bad, it is very bad do not do it. Get a OK gas and use the production capacity buildings on it.

Or colonise a very massive gas. fill it up with structures and then hyperform. the planet will shrink by one but the structures remain.

or take a bad planet, that you know you can max out and do so. But that only works if it is one you know you can max out (like being one if the current terraforming races).