It's a 4 head gang of 17" delta drill press heads. That is a good deal if you need a gang drill press. You could probably part out the heads and get your initial investment back. Or just think you could have a lifetime supply of replacement parts.
As others have mentioned, they are designed for production, not that great in the hope shop. Could it work, yes, but not as versatile as a standard moving table drill press.
They were designed to have a part mounted in a fixture and different bits in each head. So you could slide the part/jig along the table and drill, ream, tap, counter bore, spot face, etc. to produced a finished operation.
Similar to a production table, those tables don't (from the factory) have a center hole for the drill bit, so through holes in stock have to be supported by parallels or the like to avoid spotting the table.
To answer your question "What can I drill with this". It will put a 5/8" dia twist drill through steel, without sweating. 3/4" is the limit without pushing that machine (I have one, a 1940 standalone model).