I think the right classification should be; 1) Bitcoin and 2) other cryptocurrencies which comprises of the altcoins and the shitcoins. This would allow a beginner understand the difference and judge accordingly.
I thought that anything that was not bitcoin is a shitcoin. What is the difference between altcoins and shitcoins? are you trying to say that some altcoins are not shitcoins?
Of course, any cryptocurrency that is not Bitcoin is called an alternative coin, and either memecoin or shitcoin, they are all classified as alternative coins, which is shortened as altcoin. But the truth is that some people are just deceiving themselves, trying to differentiate and call some altcoins shitcoins or memecoins, but the truth is that there are no differences as far as it’s not Bitcoin. The painful thing is that some people believe and are deceived by the differences some people try to put on alternative coins. But even they are trying to differentiate them the same way. Even FTX coin, which was considered a good alternative coin back then, why is the coin now? So, any coin apart from Bitcoin, I don't think it's worth investing in, at least for me.
You're right with this your description. Coins are better split into bitcoin and altcoins of which greater percentage of the altcoins are shitcoins. To me I see shitcoins as those coins that have extreme volatilities that can run down to zero in days, there's nothing to benefit there and they better not invested in. Most of them are derived from Airdrops and crash nearly hours after listing.
Altcoins are less extreme with volatility as they pass through periods before it's final disappearance. Coins like the Ethereum may not be classified as shitcoins even though it does not guarantee any long term returns. Bitcoin is independent and whole, so we can also see it as the only worthy coins to invest in. Bitcoin is a great asset that gets better daily.