Given this is a PS4 & 5 game, I suspect many have come across this game but are double dipping (enthusiasts). Especially as we're looking at early Switch 2 adopters and not a broader market who maybe didn't invest in another system. But the Switch 2 version is a great way to play, comes with a collector Item (FFVII card) and watching a playthrough isn't the same as playing.

Although even then I don't think a huge portion of people watch playthroughs of games they're interested in but haven't yet had the chance to play. Personally I only watch it for games where I gave up or know I won't ever get round to playing.

Anecdotally I got my friend to pick this up, it'll be his first FF since FFX on PS2. Relatively casual gamer and so refuses to invest in more than one system per generation. Skipped PS3/360 and opted for a Switch over a PS4. The S2 will be the first time he gets exposed to a lot of popular modern AAA franchises. 

1) Many might only own one console, inflation is real.

2) People probably are double dipping because there isn't much to play on the S2 at the moment.  

3) Collectors.

4) Fandom, it wouldn't shock me if many were uninterested but suddenly are now, happens all the time in gaming when something gets ported.  

Same could be said about GTA V, yet it still regularly breaks the Top 10s around the world even after over 10 years on the market. There are many factors why this port of FF7 Remake sells on Switch 2.

So far the part 1 and part 2 of the Remake are disappointing. They should take note from Capcom.
Plus Square Enix uses an horrible anti aliasing since FFXV. That's shame because FFXIII was ahead of it's time on the graphic side when it was released.

At this point, I would like more a FFXIII Trilogy remaster.