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.