[II2II]

There is another perspective: many companies don't want their employees to use company resources for personal use. They don't want that email from their domain name to be misconstrued as official business, to be entangled in their employees' legally or morally questionable actions, or simply to foot the bill for the resources used. It is a bit odd that a business would ask their employees to merge personal and professional accounts.

It's also worth noting that using personal accounts for professional purposes can confuse things. Personally, I forward any email that my supervisors inadvertently send to my personal account to my work account so that everything is archived and is in one place. Given the amount of filtering of some services (e.g. email) correspondence sent between internal accounts also tends to be more reliable. I have seen situations where dozens of employees did not receive a vital message since it was either sent to a spam folder, or simply dropped, since almost everyone found their personal email provider more convenient.