Why do it,because there is long-term investing,mining or the possibility to do other business,including offline?
I believe that when you trade or invest, it's always accompanied by a new learning just as these two things. So, if you are an investor, then in the long run you will have to learn about trading. And if you are a simple trader then you'll get to learn more about investing.
We're not stagnant and we're going to learn more things in finance such as the crypto market and these things of investing and trading. If you are going to ask why trading and not the others? because we've got the basics of it as buy and sell.
No one can set limits for yourself but only you. If you can be a good and profitable plain investor, no wonder you can also be a good trader in the long run. Investing and trading is interrelated and is benefiting one another. Remember that investing alone does not make you profitable, but one should also learn to trade so he can make a good buy and sell and covert them with significant profits. It requires long term planning and preparation, the reason why some just focus into investing and hodling itself.