Yes, because it is our decision and no one can change it. If the need arise then we should sell our bitcoins if we really needed it. It is okay also to sell some if we feel that we need it. Earning is the way to have more bitcoins since buying some feels like a loss for me if you still have not gain anything when you buy them before.
If you are earning it then you should not worry in selling them at the time of emergencies, as if you work on it you can again get them back, but people who are buying it as an investment will prefer to hold them in long term.
Yes there are some situations that we need to consider and if some incidents comes as emergency then you must need to sell your bitcoins and you need that to convert into cash. Just like me, I am just holding some of my bitcoins for a long time but when I ran out of allowance then I don't have choice but to sell my bitcoins.
You might use the bitcoin as a collateral to borrow fiat to deal with the emergency. But if you have to sell, then just sell.