~snip~
Owning Bitcoin is always good, so you decided that correctly. Selling altcoins for it is okay, but if you want to play with higher gains or losses, then you should buy and sell altcoins. This is in most cases but with a lot of luck, you can also play at the roulette table something. On the other way, you will be very happy if you have bought a coin that has made a x10 and more. With bitcoin it will be less in the comparable time, but a more security not to lose everything, and with bitcoin you can be sure that it is denzentral.
The thing is that altcoins are basically centralized companies with no regulations or protections to the owners.
You can easily lose 100% of your money in altcoins, because they really aren't the same as Bitcoin.
But yeah, as you mentioned, it's a bit of a gamble, like going to the casino. Although the casino always wins. Keep that in mind.
Bitcoin is the best but the use of altcoins can be a good investment opportunity, the problem is that the holders should not completely rely on one altcoin but many so that when one betrays the others will be there. Altcoins have their advantages in crypto investment, some will earn very fast return when Bitcoin will be moving with a snail speed. Nothing is bad in having your Bitcoin and altcoins altogether, is a way to reduce your dependency on one, you may only let your bictoin to be more for the safety of the investment to be high.
Altcoins are not private and the decentralization of many of them is a lie and many of them can lead the owner to sudden bankruptcy when they decided to be seized for any reason. But not every of them, some are decentralized and offer you the privacy you desire.