That's stupid. Why the hell your concentration will be splitted? Oh, I need to do 2 things, that's sooo haaaard, better to do nothing.
I agree, you can do both and there would be nothing wrong with it. You can always play and invest at the same time. Just make time for each one and don't really do it "at the same time" like at 1pm you gamble and invest at the same time. That would really cause a lot of problems if you do so. Schedule a time for both and you'll be fine.
That's right if you are gambling or trading then you need to give your active participation in both of them as you cannot simply put your money in it and forget it and in trading you cannot afford to miss any single fluctuation and if you do then you will miss an opportunity of making profits.
If one is going for quick profits from trading, then they need to worry about every minute and second, and it is almost same as gambling. Because in this kind trading no one can predict the prices very accurately and mostly depends on luck. But you buy some good coins and wait for prices to go up then no need to look at the prices every second.
Quick profits is not that hard in trading but in gambling it is always hard. There is greater risk to lose more money in gambling than if you are trading. Though in trading it requires a high level of skill to do which is not required in gambling. In gambling you just need to roll the dice, and you're either poor or rich. That is so different from trading.