Well, after a major correction is usually a good time to invest, but you should also look at why something crashed and if any weaknesses were exposed. One drawback to BTC, and others, is that the maximum capacity for transactions has been reached; that means you may have to wait a few days when you want to buy or sell while the price changes. Steem and Bitshares are running at less than 1% of capacity so transactions are much quicker, a few seconds, so if you are timing the market, this would be a consideration.
You can go to blocktivity (.) info to find the information on transaction activity by hovering mouse over the small cirlce with the letter (i) next to the CUI gage. Sorry I don't speak French, but got the jest of your question through other latin language I do speak. Good luck, whatever you decide.
Greetings.