many investors have been doing their best to advance bit coin since it was the first crypto currency.
No, that isn't right. Investors have been utilizing Bitcoin for personal gains, and not because they wanted Bitcoin to advance; it advanced because people were investing in it. These two are different things.
although some countries may not asept bit coin because they think that the moment they asept bitcoin their currency begins to reduce value but that is wrong
The actual reason why some countries are against Bitcoin is because they know they can't control it like the way they control their traditional financial systems, and they can't allow their people to use a system which wouldn't be in their control and they won't be able to confiscate funds, freeze wallets, ask for proof for transactions, etc.
And in doing that bit coin will finally become a word wide decentralized crypto currency in the nearest future .
Bitcoin is already a globally available decentralized cryptocurrency and it doesn't need any approval for it. Whether countries allow Bitcoin or not will only affect the adoption rate and that might affect its value in the long run, that's it.