It feels wrong to say something nice about Ticketmaster, but you don't need their app to add concert tickets to Apple Wallet (at least at all the venues where I live). I strictly use their website because I don't trust them.
I've never tried to pay with Apple Pay on ticketmaster.com, but I assume I could do that as well.
I've never tried to pay with Apple Pay on ticketmaster.com, but I assume I could do that as well.