It is the safest option to choose if you are not sure with other cryptocurreny but if you really want to trade other coins then you should choose that has strong market and is less volatile compared to altcoins which will decrease it's price for a reason. If you are on the right track then you can see that it is worth to trade. If you aren't taking the risk to choose other crypto to trade then I'd say you stick with bitcoin on your trading journey unless you want to.