I'm not really sure how to respond to this since you're not providing any specific rationale for your arguments. I think you may want to review https://news.ycombinator.com/newsguidelines.html if you haven't read it in a while.

I'll assume good faith and respond to what I think your argument probably is: Maintaining separate accounts just to prevent phishing is basically security through obscurity. All you're doing is adding some level of implicit trust to messages you receive on your "work account", which isn't actually secret and can probably be discovered by a sufficiently motivated person.