I think so. For instance, you can get “fake books” that are charts of chord progressions of hundreds of songs. Someone could sit down with this and a fake book and imitate a lot of songs well enough for a sing-along evening. It would take an awful lot more piano practice to go from zero to that level of playing.
That’s setting aside the quality question. A good pianist in the right setting’s going to sound way better than a newbie with an Omnichord. However, the newb and their Omnichord would probably be a lot more fun at a house party than not having live music at all.