It's okay if you know when to sell high and when to buy low. BUT...

Did you count how much your time costs when you're trading all the time?
How do you know if the price won't back to the previous level? TA? What if...?
What to do if your portfolio consists of ±10 cryptocurrencies plus you are able to exchange them in different exchanges?
Which is better to hold BTC or altcoins?

Of course, it's different if you're only on BTC.

Sum up all the q/a and you'll see the differences.

Also, everybody are smart to look at the history :) Good luck ;)