Wikibuy, which I use, is far more suited to online purchases such as those from Amazon. (Honey is a similar service). This is because in many cases, people shopping at sites like Amazon are looking for the best deal. Customers on OTA sites are more specific in their needs. Yes, they want value but they are not comparison shopping.
STRs can’t be easily compared after all. On Amazon, all Wikibuy or Honey is saying is ‘you can get this same product cheaper’.
With STR, there is rarely such a thing as ‘the same product’.