Personally I'm using a business acount because it's required for paying taxes. Other people might use personal accounts and try to not pay tax (untill they get caught).
Yes as MMor said taxes and I believe the business accounts you can also recieve and dispense more, you daily input and export might be a load more. Just something to think about.
Thing is, in order to open a business account, you need to enter a business name (mandatory field). So, do actually need to register a company in order to open a business account, or... ? :/