Note that times have changed, and what <b> used to be for back in the <font> and <center> days is not what it's still for. It's just a letter now, not short for "bold", with the following official definition:
> The b element represents a span of text to which attention is being drawn for utilitarian purposes without conveying any extra importance and with no implication of an alternate voice or mood, such as key words in a document abstract, product names in a review, actionable words in interactive text-driven software, or an article lede.
Same for <i>: that's not short for "italic" anymore, it's just a letter now, and is defined as:
> The i element represents a span of text in an alternate voice or mood, or otherwise offset from the normal prose in a manner indicating a different quality of text, such as a taxonomic designation, a technical term, an idiomatic phrase from another language, transliteration, a thought, or a ship name in Western texts.
So go nuts: don't use <strong> or <em> if you semantically just needed <b> or <i>.
> The b element represents a span of text to which attention is being drawn for utilitarian purposes without conveying any extra importance and with no implication of an alternate voice or mood, such as key words in a document abstract, product names in a review, actionable words in interactive text-driven software, or an article lede.
Same for <i>: that's not short for "italic" anymore, it's just a letter now, and is defined as:
> The i element represents a span of text in an alternate voice or mood, or otherwise offset from the normal prose in a manner indicating a different quality of text, such as a taxonomic designation, a technical term, an idiomatic phrase from another language, transliteration, a thought, or a ship name in Western texts.
So go nuts: don't use <strong> or <em> if you semantically just needed <b> or <i>.