Podcasting 2.0 primarily uses keysend because it makes handling value splits very easy. Value splits are very important. Most nostr wallets don’t support keysend, so to ensure a good user experience across both nostr and podcasting 2.0, Fountain provides you a wallet via ZBD.
Discussion
Maybe Fountain adding NWC will mean you don't have to rely on a Fountain account so much. Although the wallet they provided is top notch.
As long as the wallet supports keysend. lnaddress still creates a poor UX when dealing with splits, and many podcasts still have keysend addresses in their feeds. I’m not sure we’re getting away from keysend in podcasting any time soon.