The math is something like;
- you earned 10$ in 2025 may (fictive date)
- if it is higher than the payout threshold they will try to send you 10$ worth of storj (with a 2025 may avg storj-usd price)
for the send, they need to pay 2$ worth of gas for the eth network, so they will send you only 8$ worth of storj- for the send storj labs pays the 2$ and you get all the 10$
If you go to L2 the transaction fee is lower, and the price to convert L2 to L1 can be paid when you want to convert , so instead of losing 2$ every month, you lose 0.1$ every month, and transfer for 2$ once at the end of the year, and you get 20.8$ profit compared to using L1.
All of my prices are made up, I have no up-to-date info what are the current transaction costs. Ofc. Storj labs will not do a 50$ transaction for “free” so you can get your subdollar storj 
This is why they have payout thresholds.
EDIT: fixed my statements based on the below posted source.