Since the early days of SEO, SEOs have been looking for anything to tweak on page to impact their rankings - including using the bold tag on your text. If you want to emphasis words on your page, you bold them on the web and they stand out.
But does that give you a little more ranking weight for the keyword you bold on your page? It might says John Mueller of Google. He said "you'll probably get more out of bolding text for human users / usability in the end." "Bots might like, but they're not going to buy anything," he added.
Here is the tweet:
You'll probably get more out of bolding text for human users / usability in the end. Bots might like, but they're not going to buy anything.
— John ☆.o(≧▽≦)o.☆ (@JohnMu) July 6, 2017
I don't think many SEOs these days would say the trick to rank well in Google is to use a lot of bold tags on their page.
Forum discussion at Twitter.