I agree. This position is expected to have big names in music who has like 10+ years of experience. Back to 7 years ago people were furious that Miley was announced as a coach but they kept forgetting that Miley herself already had 10 years in the industry at the age of 24.
I remember Ellie Lawrence were salty that she had Selena Gomez as a Battle round mentor, and the Gwen season after that they had Celine Dion.
I think what they really care is ratings and also believe that sometimes those "low profile" celebrities' team has approached NBC for a possible spot, and TPTB can happily make a deal out of it. The celebrity can get a career revival (as Adam and Xtina experienced), and the show can cut budgets.