The concern with cryptocurrency-related services is probably more around scamming and illegal business operations than mining as -- as you say -- mining should be relatively easy to detect.
I'd say if you want to run gray area services like crypto, porn or gambling, you should probably ensure in advance that the provider is okay with you running your service, not just that they don't explicitly list your use case in their ToS.
A few years back, I used a hosting company that was pretty lenient with the stuff they allowed. It was used by a lot of gray area or slightly shady websites. I didn't really care about that, but they suffered frequent outages because some of the shady sites were constantly being attacked. So I switched to a different hosting company that was stricter and did not constantly suffer from outages.
While researching EU alternatives to Stripe I ran into a payment processor that advertised itself as being a great fit for recurring subscriptions with plenty of payment options and good rates but the website looked like it was designed a decade ago. After googling the company I realized it's primarily used in the adult industry. Nothing against them but not the kind of associations most companies want when people google the name on their credit card charges to figure out what they are.
The problem with building a platform that distinguishes itself by not having specific rules is that it attracts primarily people looking to do things that would break those rules and that this creates an environment that can drive away anyone else. This is as true for business services as for anything else.
I'd say if you want to run gray area services like crypto, porn or gambling, you should probably ensure in advance that the provider is okay with you running your service, not just that they don't explicitly list your use case in their ToS.