So basically you're thinking of a wallet that can only be used to send tips to websites, instead of a wallet that can be used to send coins to any address?

I would like to have an app for sending small tips if it's off-chain and operated by a trusted party (for instance an exchange or online casino). Small tips aren't worth paying transaction fees, and an off-chain solution would be nice. LN could work, but for small amounts I'm fine trusting a third party too.