However in investment we should make good decission to avoid lose
Investments will incur losses, without that it is never an investment at all. 
Of course the point of savings is to provide funds in case of emergency. You might be able to milk that Bank's fixed deposit rate but it will not lead to huge returns. On the contrary investment carry a higher risk:reward ratio and they might be able to give you higher profits depending on the type of asset.
Hence we need both of these to be able to sustain a proper future.
Yahh that's right we can't fully invest all the money we have to maintain a balance so that it's all what is needed, with an emergency fund you will not cross out the ongoing investment so when there is no emergency fund investment funds will be withdrawn to make needs even though it is not on target.
With investment we are free to choose with high / low risk but with high risk they will be faster to get rich but it's not a matter of easy or not it depends on how you do it because it requires skills that are mastered.