At this time, investing is preferred. For you to be rich in cryptocurrency, you have to put your eyes when the price has gone down. Investing in such time is always profiting because price might have touched the buttom and getting ready to leave the bear mode.
Investing is always the most preferred way to go when it comes to any bear market. People tend to get scared away from bear markets, but investors always see it as an opportunity to always buy the dips and be patient for the long term as you would not miss it at the long shot of it as long as you are picking the bottom. So, in most cases, it depends on how everyone is picturing the market and the opportunities they are seeing from it, which means it takes being smart to be able to make good market decisions.
Coins will be worth as much as they are used, and every coin will have a certain amount of money to counter inflation as well.
Yes, the worth of a coin is being decided by its application in real world and not definitely due to being rare. Probably OP is denoting "rare" in terms of demand, i.e. when there will be more demand then a coin will become "rare".