I don't understand the blowback you're getting over this. Super standard money game strategy. You don't even need to 'get in their head' as much as just seeing your pace will mess with theirs subconsciously. Like someone else mentioned above that they adjust their pace to the other player's...this happens without us realizing it too to a degree and it is possible to take a fast rhythm player out of their preferred rhythm just by playing at a pace that is way slower....and ye, 30s is waaaaaaay slower than like 12s and if balls are close a 'speed demon' takes way less than that too.
I myself prefer to play fast and see guys trying this on me all the time. It's cute. I can play any pace and am probably best at a deliberate, double check each shot from the other side kinda pace. But when I get going around the table, it just looks better and more impressive cuz there's just something more intimidating about a guy running out in a 1min/90s instead of 4/5min. I bet at first the foot dragger thinks his plan worked and he broke my rhythm but all it does is ensure he dies a slower death (and I'm no world beater by any means but guys better than me don't bother with any of these tactics and are happy for me to fly around and get killed even faster lol).
Yesterday I came to the table to warmup for a match and there was a league 8ball on table next to me. I threw out the balls and ran 2 racks before the guy playing 8ball finished his turn. I get that there's a lot more to think about in 8ball than on open runs of 9ball, but if fast players are speed demons, guys like that are just demons, sent here to torture the rest of us with their lullaby games. He'd make Takeshi Okumura proud tho....that guy took 12min to shoot a ball vs Earl in the 2002 Quarters or Semis. Even edited for TV they spent a few min talking about it. But at least that was a world championship not some random Tuesday league match against a lower ranked player.