Since Bitcoin is said to be the costliest of all in the crypto market the fluctuation in its price affects other coins
this is to say when the bitcoin price drops, every other coin drops in their market price so drastically that will be noticed easily making them attractive to buy following the fall
this method will enable one to gain more coins than expected, following the records most of these coins have gone high in time past when the bitcoin price went up so buying more when the price falls seems to be a great trick on acquiring much more coin than expected, this is to say the fall enables us to use less fiat to acquire more coins
will you advice other users to purchase weaker coins when the bitcoin price drops or buy the bitcoin itself?
Sometimes when the price of BTC drops, some investor or big whales that hold some huge liquidity of some altcoins or meme coins use that opportunity to pull out their profits, and the price of such coin goes down stylishly and never to come back up. If they use the bearish trend of the market to take their profits, then it won't look like a scam to those interested in buying the coin.
So, not every coins is worth buying when the price drops.