I don’t claim to have an informed opinion, but your boat insurance policy likely has coverage for towing. Take a look at it and you may find that you don’t need any additional coverage.
If your boat is the Fleming that I seem to remember, it seems unlikely that a tow would be the solution to a problem. In the unlikely event that a tow is needed, most yacht policies cover it.
I've been looking into tow insurance for the same areas for my trailer boat. I found BoatUS does not cover much in SW BC. There seems to be only one service provider located in Vancouver. https://www.boatus.com/ServiceLocator/ As mentioned above look into your yacht policy. My big boat is well covered.
Reading the fine print of those towing company subscriptions, I decided it was not worth it. Even the "unlimited" ones are quite limited. I'll depend on the insurance policy tow coverage, which is extensive, covers any towing facility locally available, and already paid for.
Belt and suspenders I guess. For me, it’s about divers to recover stuck anchors etc.
Not sure what “soft groundings” is in their description. Not too many soft groundings in BC I would think!
I did have to hire divers when my anchor was stuck under an abandoned concrete mooring block over an old naval anchor - and the diver told me insurance would have covered them from USBoat but not C Tow.