I asked and got an answer..

“Currently, we are paying the fees for our users with funds that were given to us by our investors. As we roll out new features, and bring the app closer to being out of beta, we will introduce a fee structure for on-chain payments, as well as much smaller fees for payments to other Lightning wallets, which the users will have to pay. We plan for NOAH-to-NOAH transactions to always be fee-free, however.

Please let me know if you have any questions. Have a great day!”