Breez and Phoenix are great, but for an absolute newbie with 0 sats wanting to get a couple of sats through lightning muun is the only non-custodial option that actually works in that case.
Interesting; Breez once was free deposit as well. I remember asking them how they're paying for that / how it makes financial sense and they said it was only like that for the beginning and it was subject to change.
To be honest - and I'm going on a tangent here again, sorry for that - 2,000 sats is right now around $1 and while less magical than anything 'free', it teaches somehow the right lesson. 'There is no free lunch' is an important part of Bitcoin for me, so in a way it's not wrong that newbies are shown right in the beginning that over here we do pay for e.g. securing our seeds, creating payment networks and stuff like that. But compared to fiat land, we don't pay with our souls by handing over KYC to banks or having our purchasing history data milked by credit card and reward card companies.
Keep in mind (at least last I tried), muun puts a large portion of funds on-chain as soon as it reaches some threshold. It's also not visible anywhere what portion is allocated how, so you can end up sending 100,000 sats via LN to muun and then not be able to send 50,000 out to another LN wallet at super low fees + fast speed, which is something you'd expect from a LN wallet. However, it may be indeed better for very small amounts due to no setup fee. But I'd recommend to send those sats to Breez or anything like that once they start to stack a bit more.
This may all have changed; but still not being able to see which portion is on-chain and which is in LN makes me uncomfortable using muun.
You could seriously also just onboard new users through BlueWallet. It has no channel setup fees; sure it's custodial, but we're talking about people who don't have 2,000 sats to open a channel. There's not much to lose there. And it allows them to create non-custodial Bitcoin wallets in the same app, buy Bitcoin in the same app and also to send those Bitcoin into their LN wallet from that same app.