One could also give 10% discounts to customers who pay in BTC.

I pay groceries and my beers in sats with a 10% discount (because I pay in BTC). See more about an adoption story I wrote some time ago.

When I onboard merchants I always tell them:

• charge 5-10% more if customer pays with VISA (make them pay and feel the pain)
• charge 3-5% more if they pay with bank transfer
• charge with discount up to 10-15% if they pay with BTC. If you hold those sats, you will not regret it.