If you go to r/churning back a few years, people were getting 24 new cards a year. Open the card, buy $4,000 worth of gift certificates, claim the reward, close the card, repeat. It was insane the amount of effort people put into it.
Banks creates these rewards to incentivize people to open the cards. Chase did eventually put a limit of 5 cards in 24 months (a limit I have hit), but they just reject you for the card off the bat.
In terms of the credit score hit, it's minor. I've never had my score change by more than 5-10 points. I wouldn't do it if I was applying for a mortgage in the near term, but otherwise, it doesn't really change my score as 5-10 points doesn't change the band you're in.
I'm well aware of 5/24 -- I might suggest that if people are shuffling things around that much, they deal with Chase *first*, before looking at other issuers, just to be sure those applications don't get denied.
I might be totally off base, but this seems like it can't end well.