Debian doesn't care, but the programs are generally developed for a laptop or desktop sized screen. Let's say 10" and above. My guess is UI and UX will not be smooth or really all that usable. Touchscreen for a PC-like UI on a screen that small? Can't imagine it would be nice.
I'd honestly love it to be fantastic, it would be great to see. But I think it being a "Just Works" device is unlikely.
And on Sailfish, length of development time is slightly irrelevant. If there's not many people using it then it's unlikely to progress and improve. I realise mass market OSes are dumbed down somewhat, but I doubt a no market OS will be so great.
EDITED: 17 Sep 2020 14:52 by ANT_THOMAS