It's better that they don't use lightning since it offers no benefit here and using it promotes it to people unaware of how much it sucks
Discussion
they would have gotten more sats from me instead of those sats going to onchain fees
plus there are privacy benefits which are obviously of interest to Tor
There shouldn't be any privacy benefits for them since they're probably using Tor to begin with
And they shouldn't care about the few extra sats compared to the convenience and security of on-chain Bitcoin