It has been a normal talk that investors should invest in bitcoin with discretionary income, which is the money they can afford loose. I will not entirely dispute this statement, but I would say, this statement is majorly for newbies who are still learning bitcoin, and yet to fully understand how bitcoin investing works or for those investors who don't have strong financial strength.
First of all your definition of discretionary income as money that you can afford to lose is totally wrong. Discretionary income is actually money that is left from your income after you’ve settled all you bill for the month, week or even daily depending on how your income flows.
We all know that Bitcoin is a store of value, which means the more you hold bitcoin, the more the value of your portfolio increases, so for this reason, there is nothing wrong if you go beyond your discretionary income.
It’s not like it’s totally wrong to use another funds apartment from discretionary income to invest in bitcoin but they don’t want a situation where you will start think about selling your holdings prematurely when you are stretched a bit financially.
Summarily, bitcoin is just like other investment that people are investing huge amount of money into, so investors should not entertain any fear, not that you should invest all your money in bitcoin, but you can invest beyond your discretionary income.
Bitcoin is a safe, and genue investment, you only need a secured wallet to keep your asset safe, then watch your asset grow in the long run.
Bitcoin isn’t like every other investment due to it’s volatility nature so you can’t compare it with other investment due that are not volatile in price of the asset it self, you thats why bitcoin investors emphasize on buying with discretionary income and also holding for long.