How does Muun even make money?

I know Muun is not a real lightning wallet (I use Phoenix for that), but I've found Muun perfect to reduce withdrawal fees from exchanges who support Lightning (Kraken).

Withdraw from Kraken to Muun for free using LN (avoiding the jacked up Kraken L1 withdrawal fee), then withdraw from Muun to your hardware wallet only paying the real mining fee.

Since Muun is all submarine swaps, they have to pay L1 mining fees everytime you withdraw to Muun. Since I was testing it for the first time, I did 4 such withdrawals to Muun. Then, you have to pay the L1 fee yourself when you withdraw from Muun.

So I made Muun pay 4x L1 mining fees (I checked the blockchain) and they did not impose any fee to me during the entire process outside of the normal L1 fee, so they got 0% of my money.

Am I missing something or did I made them lose money? When does Muun even make money from their users? Thanks!

(Auto-deleted from r/lightningnetwork for some reason, so posting it here instead)

UPDATE:

Muun refuses incoming Lightning TX when L1 fees are high. This kinda confirms that they do lose money on every deposit because they pay miners every time. I'll simply use the normal Kraken withdrawal instead in those cases. So Muun never loses too much money at once, but I still do not get when they win money...