In the UK, "homeowners insurance" definitely wouldn't cover you for Airbnb style scenarios, and most "landlords insurance" wouldn't either, e.g. because you needed formal tenancy agreements (e.g. Assured Shorthold Tenancy), no potential for long void periods etc. However, some specialist insurance companies would insure you for Airbnb style scenarios via "holiday let insurance". You'd still need that cover because AirCover only provides insurance for the period while guests are there, i.e. you would still need insurance for break-ins, water leaks, cleaners injuring themselves, etc. in-between guests.
So this supplements rather than replaces your existing insurance. Not sure why this is so prominent on the HN home page because it isn't really something "that good hackers would find interesting" or something "that gratifies one's intellectual curiosity".