Phoenix refuses first-receives under a threshold and generally has relatively high fees due to liquidity allocation and on-chain costs. Graduated wallets allow the LSP to allocate substantially less liquidity and allow the first receive to be as low as a zap. It’s a much better UX if you get all the pieces working.
Discussion
The phoenixd server handles small first receives differently than mobile app Phoenix. The fee credit system might be interesting as a comparison, with the main caveat that small receives are only accumulated until they can be used to open a channel.
I don’t find the “fee credit” system interesting for a consumer product at all (and I guess ACINQ broadly agrees given they don’t use it in Phoenix). The first payment is *the* experience that a wallet has to get right (and then every other payment but the first one matters a lot). If the first payment is just “thanks for the money, we’re keeping this to pay for fees in the future” I don’t buy that people would keep using that wallet.