I think its the following:

Very sticky business, low churn, seems fairly stable, kicks off over $1B of FCF that historically goes towards buybacks. Currently they're going through a cap ex cycle so not enough cash for major repurchases, but end of next year company signaled that will return to more meaningful buybacks.

It's 38% owned by Berkshire, once they start repurchasing shares this should materially help EPS, they would be buying back 15% of the company each year or thereabouts. I think that's the end game. Very similar to DVA in that its a stable business and all FCF goes towards repurchases. This is Ted's MO. Same thing with Dillards.

This is my take anyway.

Obviously they're competing with Spotify and young people likely won't be subscribers to SIRI the same way old boomers are, so I think that is the negative view.