A lot of us here are using both. Similarly my iPhone is my main number for messaging, contacts, telephone calls and email. TBH, no android phone I've ever had works better for handling legacy .mac email accounts than my iPhone and Mac do. Plus messaging being accessible and with High Sierra proper syncing / unification between my desktop, laptop and phone - for work stuff it simply is a no brainier for me to keep iOS as my work tool.
I still sync my emails to my android devices but they don't support push,only fetch and sometimes there are delays or annoyances when deleting them. Gmail has a habit of going through process of deleting and then brings it back as a new message, thus requiring deletion again.
Likewise I can't keep track of my text and iMessages from work clients as well as I can on iOS with message forwarding and answering from my computers.
My iPhone however barely gets used for music or YouTube or social media. Barely even use the camera despite it being a great camera generally. I tend to do all that on my android devices.
It's a setup that works for me. iPhone for work, Android for media consumption and camera / cameras.