"With the liking system, we could see which advice is more valuable, and which should be taken with a grain of salt" - that is exactly like the answer system. I see no difference.
In any case, if there's advice that's not practical/ good, more experienced users will call it out.
Also, I know it's shocking, but comments are sometimes... just comments? They don't need to be pieces of advice, or any extra information, but are actually opinions, or just random observations. I don't think it would be fair to give or take points for someone's opinions.