It won't get banned by some services, you have complete control over the domain and account, you can send email from any address you wish, you can sign up for domain-wide haveibeenpwned alerts by verifying domain ownership via TXT records, and you don't have to worry about the service going out of business in 2 years.
After going through my password manager last year and changing as many logins and emails as I could, I've found several services that have sold my email address to third parties and one that was hacked. It's a relief to know I don't have all my proverbial email eggs in one basket.