I think teams expect the Sox to have benches like WBC teams. Yes the Sox backup catcher cannot hit. Know who else has that issue?? Every team in MLB! The Mets, with a payroll north of $300 gazillion dollars, have Luis Torrens as the backup. Their little sisters the Yankees (payroll wise) use career minor league JC Escarria behind Austin Wells. The Phillies, lead by free-spender Dave Dombrowski, have Rafael Marchan, who I believe did not play major or minor league baseball last year. (Source: Roster Resource. Final rosters might vary.)
Some teams like the Dodgers (Dalton Rushing) and Orioles (Sam Basallo) have backup catchers who were top prospects that will likely move to other positions in the near future. Just like the Athletics did with Tyler Soderstrom.
But for the most part, backup catchers are the punters of MLB - they go from team to team silently and only have one skill useful to their sport. Expecting a backup catcher who can catch and hit is like expecting the punter that can catch passes and block…