Yes! In fact, in practically ALL applications it's better to work than not work at all. The only exception I can think of is directly-interactive software like

Yes! In fact, in practically ALL applications it's better to work than not work at all. The only exception I can think of is directly-interactive software like video games and VR imaging, where minimum fps really does matter. Many situations for various customers aren't massive datasets but modest sets, so you might be on the left of the J-curve. Requiring 2 seconds, instead of 0.2 seconds, for a result is simply not important in most cases. I think it's fair to warn the user that "GPU acceleration not working" if the performance is expected to be much better with a GPU.