Whilst there are metrics out there for dead coins (no market cap or no liquidity for trading), a coin may still be alive and traded regularly, but still I don't think any alt coins should be in someone's portfolio. Alt coins are created to make the owners wealthy primarily, or become highly centralised and governed by organisations with selfish intent. The only one free of this is Bitcoin..
For special elections, it is true, BTC is safest to invest in and indirectly in terms of the most similar price if we look at it, but for other than bitcoin, each exchange sometimes has price differences, although not far away.
Well, I agree if you relate many glaring weaknesses such as the potential for centralization and its speculative nature to altcoins but outside there are still many investors who are also focused, placing high hopes on altcoins because there is an assumption that it still has promising potential and growth.