Essentially just the title. I think it's cool that the BIT Device itself changes when you pick one of the pre-made BITS, and it would be fun if we could make it colors that match a Custom bit too.
Mostly for other players reading this: Obviously it would be amazing if we could just make a custom device, but I think that would be asking too much. Interface design is hard enough. I think there's a good chance custom colors could be added to the custom files without asking the team to redo how the buttons work.