If you are a beginner, then you do not need to trade anything except bitcoin. Experienced traders can determine the perspective of some coins and make trades with them because some altcoins look quite interesting in the long or medium term.
There are good markets which have huge volume such as usdt and ETH which have a lot of pair in altcoins. I think it's good not to just stay in the market specially during bear market.
iit's true that besides trading Bitcoin I also trade ethereum and other atcoins because it's good enough to get results other than bitcoin and the results also promise if in my opinion