UL is a litigation shield. Policy is that many won’t install anything without it because then they are afraid to be liable. Depending on application it may have nothing to do with law. The only law a consumer really has to deal with that’s UL, is that some counties in the US prohibit sales of non-UL items. You can obviously get around that by going down the road or ordering online. (And truthfully no one probably knows they are in one of thise counties)
Here’s the real problem... I can sell you a UL PC, but there will be around a $40k surcharge distributed across projected amount to be sold that year.
You may notice that CE is more common with audiophile products. That’s because small businesses cannot realistically afford UL certs. Sometimes special situations allow them to under a parent business.
Not having UL on a product doesn’t gurantee that insurance won’t cover something, it just means there is a defensible process that follows - as opposed to automatically being faultless. (If you can’t afford a lawyer it might be an issue, you need process to have someone qualified to explain whether something was reasonably safe or not)
Probably the vast majority of audio products owned by memebers here don’t have UL. While I like that it exists to keep us safe from only-god-knows-what china might send out way without it, it is impossible for small business. Even finding out what requirements are can be very expensive before you even start dulling out new car level payments for certs.