Bitcoin is definatly worth investing in and is here to stay, i reckon bitcoin will be in the 6 figure region within 20 years.
I am not sure It will be 3 or 6 figure But sure It only rule the world currencies and It will be familiar to all the people in the world Because Its digitization, Value among the other currencies will make their future people choice and Bitcoin is worth and best decision for the who are all saving the bitcoin as long term goal.
I dont think people just want coins instead of their cash. that is only because of the things you can pay with bitcoins you cant buy or pay
everything with coins and you can with cash.
If you asked me, I better choose coins instead of cash. Why? Coins make me profit without doing anything if I just stored it. What about cash? Does it make profit by just storing it?