@Phedra1
Having signs or stickers all over the place is tacky anyway, even if you're not trying to sell something. There is a lot of feedback on social media, if you care to look, about how much a lot of guests absolutely hate this. It does not make for a pleasant stay if it's overdone.
Of course, there are more subtle and less pushy ways of going about these things and I believe that it can be worth doing if there is a financial benefit to the guest, not just to the host.
So, I will recommend certain food delivery services, for example, where I get a small referral discount, but the guest guests a whopping discount, and only because I have tried and tested these services, know they are good and the guest is getting a great deal. Even then, I do not shove it down their face. I don't even mention it until I evaluate whether it is something that would be useful to the guest.
There are some more high end places where certain things like artwork and furnishings are available to purchase and I don't think that's a bad idea. The guests are told that they are an then the onus is on the guest to enquire if they would like to buy any of it. Again, it's not covered in signs and stickers and QR codes. Most guests do not want to pay for a listing only to find that it is covered in signs trying to get them to spend money for the benefit of the host.