Why would I want to keep BTC in my investment portfolio? That's most hyped and quite overvalued coin I'd say.
There are other more technologically advanced coins. Is it because of "digital gold" and store of value properties?
Many people have invested their capital to Bitcoin because they can see how this will help them to gain more income. They usually buy low and then hold it for a long term period until they reached the desired income. Many people are now wealthy because they placed it last year and hold, today it is really a high price. Since early this year until today, Bitcoin really performs well, mooning, that gives much earnings to investors. So, we better to buy Bitcoin now and hold until early next year because there's a speculation of price will increase.