A website is a tool, a means to an end. The purpose of chat popups or feedback forms is to further a business goal, not to increase the website's usability.
No, the business goal is to lie, trick, cheat and steal, to fuck a potential customer over so they part with their money.
That the customer may not be satisfied afterwards doesn't matter - there are plenty of mitigation strategies, such as lock-in effects, playing off sunk cost fallacy, or drowning negative feedback on third-party sites with bought ratings, reviews and social media likes.
Seeing a site like this should light an immediate warning site in your head, telling you that you don't want to be on the business end of their business goals.
I myself am blocking these annoyances with an adblocker so I'm in the same boat as you.
That being said, the value that these patterns are gaining the businesses that employ them, must outweigh the value lost from people who are so annoyed that they take their business elsewhere.
I had a support chat on my business website for a long time; the "business goal" I wanted to further was to make it very easy for people to talk to me, ask questions, etc. I helped out a lot of people with very short turnaround times.
I removed it mostly because it takes a lot of effort to maintain a good level of responsiveness on these kind of things unless you have a dedicated support team.
Some of these support chat popups are a bit too in-your-face, but it sure beats hunting down some email address somewhere.