As someone who has joined very late in the crypto race, I find that owning just BTC is not an effective way to get up to speed very fast. The potential upside totally pales when compared to the (good) altcoins. I would much rather trade or hodl alts in a bull market than hodl bitcoin. Of course I do my fair share of trading to optimize my gains even more but I am an experienced trader with prior background in stocks and forex, but the average beginner would probably still be better off hodling altcoins and maybe 10% BTC.
Now, if I succeed in creating a sizeable portfolio of crypto assets then of course I too have the objective of owning one BTC for the long haul!