I would add to this theme that it's important to always watch where memcoin is listing. If it happens exclusively on pancakeswap, then you should definitely stay away from such a coin, because on this exchange mostly all sorts of scams appear, and such projects don't live long. If memcoin is listed on other exchanges, more famous, then it is not so clear.
Generally, meme coins are listed in other more famous exchanges or centralized exchanges after they've got enough community hype and the centralized exchanges like Binance have seen some demand for them by their members, that is when they add those tokens since they know people will trade them and they will earn revenue from fees and stuff.
For me, even if a meme coin has been listed by a popular and trusted exchange, I wouldn't still invest in it since their hype is mostly only a one-timer and they tend to just drop and drop and stay stable after the hype is over.
Right, because centralized exchanges are much more popular among crypto investors and have much more liquidity concentrated there. Listing memcoin on a centralized exchange almost always guarantees a sharp rise in the price of that memcoin. One big disadvantage of all this is that if memcoin is already listed on a centralized exchange, it will be extremely risky to buy it because the price will already be quite high, although it may still rise. If you bought memcoins on a decentralized exchange before that, and after that there was a listing on a centralized exchange, then you are very lucky.