That can be useful. A playtester with more experience can often be more helpful.
I think my overall message though, was the same as a somewhat popular saying, it's "Too many cooks spoil the broth."
Viewing post in The benefits (and pitfalls) of playtesting
You should also distinguish between someone testing the game and someone playing the game and giving feedback. It might look the same in some cases. But there is a fundamentally different approach and different expectations.
This also overlaps, when people play games they know are still in development.