2. You Will Loose Your Motivation and Additional Knowledge
If you are serious about your online business, then having your own web hosting is a great ways to motivate your own productivity through blog. How this could be? You have to spend some amount of money to have your own web hosting, this could be your investment. And of course you want your investment yields something right? Thus you will make your best efforts to make those yields.
For example I have bought web hosting from Host Gator for 3 years package. Thus I start make a plan on what I want to achieve in the next 3 years using the services. (at this writing, I am having free facilities to transfer my data from wordpress to hostgator). I become more motivated in making blog contents because I do not want to spend my money for nothing. (this is my extra motivation).
Besides that, you will have to deal with the technical things on manage your own website. Doing this will makes you unconsciously become better acknowleged on such a technical matters. I am not an expert on these technical matters, but from my experiences, the live chat services will give a lot of helps to overcome problems that occure during this activity. Prominent web hosting should have 24/7 live chat features that you can use to solve whatever your problem is.