Bitcoin is not everything , you can still have a good portfolio without it.
Why add Bitcoin now? It maybe 2x this year from current price and will then spend the next 2 years after that going down in bear market.
Altcoins in the current top 100 or so give you a good chance of making very good money this year, Bitcoin doesn’t.
Buying Bitcoin needs you to accumulate huge volume of it to get huge gains, using $100 to buy Bitcoin will only give you little quantity which might give you little gains after a major increase in price of Bitcoin.
I only advise people and myself to only buy good quantity of assets to gain a massive gain when the assets rises.
That's why I prefer to buying meme coins especially the ones listed on top centralized exchange because of the quantity accumulated , any little price increase brings more gain to your capital.