I use catchall domain for... everything. Every account at every entity has its own unique address, since probably well before 2010. I have always more than happily accepted to have my address saved into marketing databases.
I can share the frustration sometimes with employees turned sudden internet experts and "teaching" me that my email address cannot start with their employer's name. I usually retaliate by withdrawing my consent to be registered into their database.
And that ends there, I disagree with everything else in the blog post.
1. Catchall facilitates blacklisting when it becomes necessary: whatever rotating address is used by the sender, I blacklist myself as the recipient.
2. It helps detect who shares databases with whom. This is not necessarily about "selling" but more often it taught me which companies operate with which companies under the umbrella of that "and our partners" statement found in every privacy policy written by legal consulting firms.
3. It's a smoking gun for companies wbo get hacked without even knowing it. I have been informed several times of a compromise before the company itself knew it.
4. I also use suffixes on my catchall addresses, this allows me optimize my email filters.
5. It makes correlation more difficult across databases and anything that helps achieving this goal is a win for me.
6. I use a password manager, I use both the login and the password fields. The title of the entry always allowed me to find the account very efficiently.
I can probably find other reasons, I'd just conclude that after more than 10 years using a catchall domain, I still can't imagine sharing the same identifier across all my interactions.