It is actually dubbed the MiniVee.
I had one due to space constraints. That was before I discovered the wonder tool known as a sawzall and expanded my available subwoofer space. Twice. Lol.
For 9x9, it was really impressive. There was no low hz you could actually feel, but it did provide a low frequency foundation throughout our very large living area, ie, you didn't know it was there but when you shut it off the floor would fall out of the music. It kept up at high db's remarkably well and soundwise it was pretty seamless.
I think the market is there. The smallest best sub you can get is a worthwhile niche. Don't make me say the 4 letter word.
edit- my mistake! I had the minivee 8''.