I know many will say the time ended, we must have bought before 15 days but I think this is the best time. Before couple of weeks ago, BTC was around $4k and which is why altcoins are overpriced in term of BTC. Now that BTC has gained price, altcoins price has decreased in term of BTC and now is the best time to pick your favorite altcoin because right after the BTC ride, altcoin will also follow the trend.
As we see almost every altcoin follows bitcoin's price, when it rises, altcoins rise too but it's a matter of task, which will rise the most? Is it better to still stick with bitcoin or hold altcoin? Imagine bitcoin went from 5K to 10k in one weel, will price of other coins double too? Or they'll just rise a little bit because of bitcoin? This calculation place huge role here.