Accept cryptocurrency for donations

I would suggest that anyone wishing to use crypto for donations simply convert it to USD or Euros.

I always become suspicious of sources that would rather not be associated with causes they support.

I cannot speak for Lichess or their decisions regarding cryptocurrency.

I can, however, assure you that I and maybe others would probably stop supporting Lichess should they choose to accept cryptocurrency.
It would be extremely unethical to take part in a pyramid scheme like cryptocurrencies, especially since their enormous energy consumption alone amounts to an ecological catastrophe.