How is this a measure? I have my own domain, so why would I make several accounts for your service? I just need one.

And labeling a domain as disposable, when it's clearly isn't, sounds a bit strange to me.

People did that a lot to get new free accounts from disposable email services (You can generate 100 images/mo for free). Around 15% of signups were disposable email multi accounts (40% of email signups).

I use email verification API for this. It states to make decisions based on public email blacklists and lists of disposable emails. Cleary it's not perfect

Well you can also block domains from fakemail.net to prevent disposable emails.