This is a healthy trend. We could use some African-American bluegrass bands too.
It breaks down the race barrier in bluegrass and some parts of OT music.

These kids are good. Let's have more African-American banjo pickers, guitar flat pickers,
fiddlers, OT and bluegrass singers and for that matter more Asian and Hispanic also.

When a music becomes confined to a particular race or culture it becomes dormant.
What keeps it from being a stuffy museum piece is an infusion of other cultural musical ideas. (This is what created jazz, and much of what we call folk music these days.)

Frank Hamilton