It is indeed a very very bad idea to buy things using bitcoin instead of other currency.

It is never a good idea to spend bitcoin to buy your daily groceries or mobile recharge. Bitcoin should be considered as an alternate investment option.

If you are using bitcoin to buy daily groceries, then you are loosing a big opportunity to become rich.
I can agree with this, it is probably a better idea to wait with your Bitcoin for a relatively long period of time and then make your fiat money off of it first, and then once it gets accepted and a lot of people start using it and the value eventually starts to stabilize, then it might be acceptable to spend your Bitcoin on more normal things. I, for one, would certainly be avoiding most of the expenses I can with my Bitcoin.