With all of the hype surrounding "De-Fi" and NFTs, it looks like old coins like Peercoin, Primecoin, and Quark have been left in the dust. This is sad, considering that the aforementioned coins have a proven track record of stability and reliability. New coins are usually less secure than old ones. Despite the low interest/demand for old coins, they're still actively traded on the market.
I'm wondering whenever it's worth buying and holding old coins for the long term. Primecoin is one of its kind with a PoW algorithm that contributes towards the discovery of prime numbers. It's a pity other crypto projects haven't copied its model. Your input will be greatly appreciated. Thank you.

In my opinion, it's no longer worth buying old coins, let alone coins that don't have strong fundamentals. My advice is that you buy coins that have strong fundamentals and high liquidity. You need to know that Liquidity is one of the important factors that need to be considered before deciding to buy old coins or new coins. This is because liquidity can have a major impact in terms of exchange rates and future profits.