Lots of Presidential candidates have had teams of sports figures in their corner. Frank Gifford and Ted Williams were on Nixon's sports committee in 1960. Bud Wilkinson was a Goldwater surrogate and candidate for Senate in 1964. Joe Paterno (before Sandusky) gave a speech for Bush 41.
For better or worse, the American public would rather listen to their favorite jocks pontificate at the RNC podium than listen to a bunch of no-name GOP elected officials get "exposure". At a certain level, I can't blame them. Politicians generally don't say anything more substantive than jocks do these days, save for an occasional interview on C-SPAN.
Yes. And giving people what they want is not a completely dumb move, right?