Well , they say never buy in top neither when it is on bottom , because if you are not sure it is the bottom it can goes deeper!
2 points are not very stable , very top and very bottom , between those would have less risk .
Well, you may not really see buying the bottom as a risk and I have noticed that any sharp drop sometimes, the market always rise up a little bit even if it wants to continue with the downtrend, but I will consider being careful with this option. I have seen drops before that really ended up dropping the more without coming back up you just have to keep holding and hoping it gets pumped back. Probably for a coin you are buying at the top on a daily chart.