I think it's that it feels like a dead product, even though it's still running.
Not a lot of new features being developed, and some features getting turned off "to support the product's next chapter"[1].
There hasn't been a firm announcement about Feedburner being sunsetted, but given Google's history of killing things off (including Reader, apropos of this thread's topic), it does feel like the walking dead.
https://developers.google.com/search/blog/2021/04/changes-to...
