Bolding in and of itself confers no technical SEO advantage. However, it does have a "soft" SEO impact in that it can make content more accessible and readable from a user perspective.

Should you bold keywords SEO?

People tend to scan webpages instead of reading every word. Bolding keywords and key phrases may not have an impact on your page rankings but it will definitely help the readability and consumption of your content.

Does bold text affect SEO?

Bold and italics DO NOT effect SEO except for secondary effects. The mark-up is relatively ignored and the text is weighted exactly the same as all the rest.