Well even then you can decide to lock away some money in your socks and when the amount is substantial bring it to the bank.
In the end it is about money control.
I wish it was that easy, the problem is they do not have enough money to have a spare to save for the future. Every thing they have is spent on daily expense, nothing left. And not everyone has net so they can work on sig campaigns. Before saving or investing, I think securing a regular incomencomes.first.
if the money is not enough to spare it, to save or invest, better to use sidejob like sign campaign, or other, and use salary from sidejob for future reference .
i save all my salary from sign campaign at paper wallet. you can see my bitcoin address ( 12345HotmWEPbRDcLCwkNN2ZWFXAhTCMB2 ) , it's small amount but if i can do it for 10years im sure i can reach 10btc