Hold is the best strategy if you can buy at low price (after the crash at the beginning of the year it's relatively that), I think the best is invest on small MC (for crypto like BTC, even if the price has fall it remains very high compared to the beginning). The best thing was to invest several years ago.

Everything depends how the market will go up in the coming years, but I don't think it's a very good idea to invest today for hold in currencies like BTC or ETH (just my opinion)

Depend too how much you invest