a trader or regular smart investor will sell at high so they can buy more in the dip. It may be short term daily trade or long term like years using bull bear cycle. This is basic knowledge
That’s one means to invest and get some good results only if you know how. This though comes with a degree of risk as, you only get to do these on CEX which means, you get to have most of your portfolio there which is highly advised against. Having all your coins and I mean Bitcoins on CEX is you have to loss custody of those Bitcoins to the exchange. You might have access to it from time to time but, that’s based on their terms and in the days that the CEX exists.
Again, the risk of having to transfer Bitcoin often makes this rather a risky thing to do. That’s because, in the event of a wrong address or obvious phishing, you could become a victim easily and the irreversible nature of Bitcoin transaction once it begins confirmation is sure to take effects.