A visa restricts the kind of work you can do for pay, but it doesn't prohibit you from receiving monetary benefits that aren't work, an occupation, pay for services, or a business.
Examples include blood donation, participating in surveys, etc.
A gift card for blood donation or participating in surveys would not violate a visa limitation, assuming that you aren't a regular paid plasma donor or a survey participant to the point that it is a part-time job or business for you.
Likewise, gambling, noted in the comments, is not a violation of a visa limitation unless you are, for example, a professional poker player.
The means of payment, e.g., cash, credit, gift card, cypto, etc. is legally irrelevant.