Just have a think about it. Why would you go and buy another account if you already have an account? What is the account for? Think about how important money is. Think about what use could it go too. Besides that it is your money. Think wisely.
It really depends on the following factors. If you need it or not? Is it worth the money? What are you going to use it for? Are you actually going to use it? If you believe you really do need, have a good/decent reason of using it, if you are actually going to use it, and if you believe it is worth the money. Then go ahead, knock yourself out. However if not, then I wouldn't.
Not to my knowledge.. I'm sure it will be fine since I've seen others do it in the past on both HC Factions and Survival.