I was a big advocate of Muun wallet before, the main reason to this was because is the easiest wallet to onboard new people to the lightning network, you just download the wallet, create a lightning invoice and receive the funds via the lightning network, you will receive the whole amount, no fees or anything disruptive to the receiver, just magic internet money at work.
The problem with Muun is that they hide how they operate. For example, if you receive 10000sats on chain you can see on any blockchain explorer that they money is there, you are in control of it and you are informed in which address they are. But when you receive 10000sats on lightning, in theory they are doing a submarine swap for you to keep your funds “non-custodial” on chain. And that’s fine but there is no way to know if that is true, they don’t inform the user what on-chain address they are using or how many. I guess the only way to know this is restore your wallet using the emergency kid they provide or doing a subsequent on chain transaction to yourself.
This issue gets more noticeable when you receive on chain funds and later you make off chain payments, because following the trail on chain you can see how the funds flow from your wallet to the submarine swap wallet. This is fine to me, they explained well they are doing this for me, but the issue here is I saw different amounts on my wallet and the on chain explorer, so here I noticed that they are not 100% transparent of what they are doing with my funds, and that’s for me is a conceptual flaw, because the main point of using a non-custodial wallet is to feel you are on control of your funds or at least know what is happening under the hood, and you can only have that if you are well informed, in this case the information the wallet is giving you is not correlated with the information you see on the blockchain using a blockchain explorer.
Here an example:
Another issue I found deal breaker for me is when you receive a big number of small payments in lightning, The wallet does a good job managing that for you and that’s one of the big selling points when you are recommending Muun wallet to someone new. You don’t need to worry about creating channels or be aware of inbound capacity.
But it can become a big issue later, because it creates a big number of small transactions on chain. And like I said before, you are not being informed of what is happening. Here an example of a transaction of few incoming lightning payments when I send all my funds to an on-chain address.
This graph only shows a small number of incoming transactions but imagine if you are a store or someone who use the LN in a daily basis, you will create without knowing it a monstrous transaction of hundreds of inputs. I think the LN should clean the Bitcoin blockchain of unnecessary small transactions, not make this worst.
To finalize I also find disturbing that Muun is the only mayor wallet that do not recognize LNURL addresses. And that can be headache later for the newcomers who wants to pay online sites that are already implementing this. I think this is vital to have a homogeneous lightning experience and for some reason Muun does not give this a priority. (LRURL auth is also out of their road map).
I understand Phoenix wallet is not perfect, it has a nasty 1% (3000sats min) fee for channel creation which is terrible if you plan to give 10$ to someone to test. But after creating a big channel the experience is the best we can have in a non-custodial lightning environment.
I don’t want to be the guy who talk bad about great bitcoin projects, but I wanted to share with everyone here my findings on Muun and help others to decide if they want to keep using it or maybe look other options.