This is in response to the OP's request in a comment to elaborate on my personal situation. This is not to explain why I have two email addresses, but just how I use them differently.
In my department (math), we have separate department and university servers both with email, and I keep my email accounts separate, though many people in our department forward from one to the other (usually from department to university, I think) and only check one.
Basically I use the department email for anything involving research or teaching or quasi-personal, as well as administrative stuff at the department level. Various factions within the university send out loads emails to us (often requiring no response and rarely urgent) which typically go to our university email addresses.
Therefore I made the conscious decision to not forward from one account to the other because almost all of these are unwanted emails, and I probably only open about 5-10% of them. So they would just clutter up my department inbox and distract me with email notifications throughout the day if I forwarded them to my department email, which I check often. I know I could filter the forwarded emails into a separate folder, but I don't want to know when I get a new university email, and having this extra login barrier helps reduce distraction.
So whenever I give my email address to someone, I give them my department email which I check throughout the day, whereas I usually check the university address about once every day or two. I honestly don't even know what my university email address is. Any email I send of my own accord will come from my department address. The only emails I send from my university account are replies to emails to that account.