In some regulations you can also be expected to declare and pay tax on the money you earned from the interest, which can be annoying to do for such small values.

Definitely annoying, and YMMV, but a lot of jurisdictions don't treat credits (that cannot be redeemed back to cash) as income.

In the same way signing up for $App and getting $100 in API credits isn't income; paying a bill early for a 3% discount isn't income; and frequent flyer points or cash back you get on our credit card isn't income.