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