Have you ever caught a marketing or spam email sent using one of your email aliases?
That's a use case for aliases, catching if any company or service gives out your email to be abused by advertisers and whatnot. I tried looking for stories but didn't find any, I wonder if you have any to share.
I got a pump and dump scam from an alias that I only used for my brokerage account. They assured me it wasn't them. A week later they publicly announced that they were hacked.