Every country has different laws around crypto, including partial and full bans, so nomads using crypto should know about that depending on where they work from. Certainly "spend from balance" and converting to local currency will vary a lot across countries, likely always more trouble than converting USD.

I freelanced and traveled full time for over a decade. Never experienced any problems with payments or US banks, or simply using US credit/debit/ATM cards. I never asked customers to pay in crypto, but I know freelancers who insisted on that and lost customers as a result. Freelancers generally don't have leverage to tell their customers how to manage payables, and crypto smells too much like risk and fraud to more than enough business people already. Introducing friction, novelty, or anything that looks sketchy into a freelancing relationship seems like a bad idea to me.

Edit: Two of the largest freelancer marketplaces, Upwork and Fiverr, do not accept or pay out in crypto.