the terms strong-bold and emphasis-italic, respectively, are used as synonyms in these lessons. Yet, the W3School explains that - while they do the same thing - there is a difference in semantics between the terms.
<i>, it says, have no "extra importance", while
Can somebody explain this in beginner level terms. I am especially interested in how this influences my choice of when to go for the ones "without extra importance" which are much shorter and simpler, and when to go for