I personally believe that Bitcoin now is reaching a stage where more and more lay people are interested in earning it and also holding it like an investment, as they would hold metals and bullion. I think it is here to stay for a few generations at least.
It seems that it might be increasing in price. Keeping Bitcoin as a investment might not be a good idea, though holding at least a single Bitcoin could be a wise choice.
Sounds like you are one of a doubting Thomas, with all the progress that bitcoin is getting,the daily increase in popularity and many big companies accepting bitcoin but you are suggesting to someone to only hold one bitcoin while there are people out there having thousands of bitcoin who are not facing any challenges but making good money. Maybe you do not know much about bitcoin.