Even without privacy, without the receiver adding any input, I think it can be more convenient. Sure, you can do PSBT based external funding, but that's still more interaction than:

1. queue up channels you'd like to open (perhaps a batch of them)
2. Generate bip21 QR code with PayJoin enabled
3. Scan & send to open as many of those channels as you have funds for

So we exchange the problem of having to open a bunch of Lightning channels with... Having a bunch of lightning channels *that are opened by others*. 🙄

It's better for privacy, sure. 

But we should aim at making all wallets communicate towards making only *batched* new opened channels. That way we are prepared for future growth and can sustain small enough blocks on L1.
