My opinion and experience says that it is better to trade the btc/altcoin than btc/fiat currency. But as many told here, it is an individual experience. Your trading might be different from others. Then go where it is comfortable to you.
I am sorry I'm unable to understand how our trading might be different from others, you mean to say we must follow different strategies so that we will be unique to make profits.
I do not think so, because we need to take decisions what other people are also making so that we can be sailing in the same direction to book profits.