Imo only if you’re gonna use two. I would get at least the 12, and ideally two. Polk has come a long way in making subs and these new ones are pretty decent, considering the cost especially. Personally, if the SVS is within reach, I’d go that way as it is better, plus you have the bill of rights, and the upgrade option for the future.
Two of the hts12 would be louder and be able to even out the bass response throughout the seating, but they’ll be all done by 25hz no matter how many you add. So for my use case, I’d get the Pb1000 and try to add one as soon as I could. Or trade it in and upgrade.