You can spend about as much on a decent upright on a good digital piano that feels good enough to perform with, and a good sound. The difference is you'll be able to resell the latter and move it easily, whereas you'll usually need to pay someone to haul away the former.

I also think that there's a noticeable difference in feel and timbre in the real thing, even a bad piano. I think it affects the way you play. Given the choice almost everyone uses a real piano to record. But gigging musicians will usually prefer a digital piano, because they can move it and trust it sounds and feels the same in different venues. Most acoustic pianos supplied by venues are poorly maintained and can have other issues like amplification (you have to mic a piano, which means you need a sound engineer at the gig, which may or may not be possible).