The reason they don't have an API is that they want to upsell you on other stuff, and get paid to promote their partners.
There's going to be a huge fight over how that relates to AI assistants over the next few years.
I agree fully, and wanted to add: for many of these services, like travel engine comparison sites, running the query itself costs money, so you do not want to make it to easy to search without booking.
I agree fully, and wanted to add: for many of these services, like travel engine comparison sites, running the query itself costs money, so you do not want to make it to easy to search without booking.