Do you understand what renters' insurance covers? As far as I know there is no policy that will cover your subletting of a rented property. What a standard renter's insurance covers is your belongings in a rented premise, your unintentional damage to your landlord's property (ex: your aquarium broke and ruined hardwood floors. Instead of your landlord submitting the claim to his/her property insurance which he/she might not want to do to avoid increase in premiums, your renter's insurance will cover the damage).
I think you are confused by the coverage the renters insurance provides that's why you are thinking that it'll help you somehow with Airbnb. In fact it will not.
As mentioned above, you are likely not even allowed to use your rented space on airbnb based on your lease agreement.
