Why BYOD? Because people are individuals.
Contrary to popular opinion amoung some corporate managers (thankfully fewer each year), employees are not their wage slaves 24/7. Their data analyst for 8 to 10 hours a day is also the chairman of the local scout troop, member of the zoning board and school board, head of a church committee, the father of 2.7 kids, the brother of 3 other family members, the husband of a careing wife, and a part time post grad student at the local university.
That's enough people to require the employee to carry a personal device for voice and image communication. That's the device used the most, the one they are most familiar with, and the one they are most efficient at using. Short of racking it at the security station before entering a restricted area, they will be carrying it always.
Now drop a second, corporate device on them. It has all the same functions, but operates differently. Apples are not Androids, and vice versa. You've added redundancy and complexity, usually unnnecessarily. You've added a learning curve, and a mental switching requirement. In short, you've actually hobbled your employee, making them less efficient. There really is no valid business excuse in today's environment that justifies making an employee less capable of doing work for you.
That's why BYOD.
