>>1242550650% of Punk's appeal now is amongst people who remember his first run and want their edgy angsty millenial favourite back after he left in his prime.
The other 50% is smarks wanting to see how he coexists IRL with people like AJ, Miz, Seth and Cody who have all publicly shit-talked him in 'shoots' and how he fares in WWE especially during election season after the last several years of his incessant political soapboxing, and willing him to fail, or destroy WWE, or both.
You'd have to be unfathomably stupid to hire him back and just go "Aw shucks business as usual CM Punk is here to just have matches and wrestle the wrestling", rather than capitalise on both the nostalgia/eternal martyrdom of Punk fans, and the backstage rumours, to run worked shoot meta angles that have the 'smart' fans thinking it's real and get people talking and watching out of curiosity. Tony Khan might be the only person in wrestling who's stupid enough to book Punk that way especially after the press conference from hell.