Over 20 years of having a gmail account I have created lots of accounts in lots of places: blogs, platforms, applications. They may hold my name, email, and depending on the the website profile and how trusting I was. Many of the websites have your data, and do not contact you, or have been sold to other companies.
This exercise is to:
a) realize the digital footprint you have
b) obfuscate and prune it for privacy, including preventing leaks of weaker passwords you might have set a long time ago
c) prune it for less emails coming to your inbox
d) prune it just for digital minimalism
e) start doing something about the gmail umbillical cord
Perhaps there are other reasons you would have for such a cleanse?