A misunderstanding of web standards

There are 91 tags in the HTML4 elements, but less than One-fourth of the labels are often used in so many labels, and two of these tags are the most versatile--div, span, These two structural labels are widely used in Web page production without presentation style and semantics, plus many people have misunderstood the Web standards directly as DIV+CSS, so there are a lot of div or span tags in a page, Although these places themselves have more semantic tags to implement.
Table-style page layouts lead to an era of web production because of their simplicity and the presence of web-making software such as Dreamweaver, which has led to the fact that too many web designers have never really focused on the true semantics of HTML tags, When Web standards begin to rise, they are directly understood as div+css layouts.
So the structure tag in the Web standard almost becomes the show field of Div.
The overuse of DIV tags has caused a lot of people to misunderstand the web standards, the most obvious point is that when the Web page switch to the use of DIV tag layout, the table label is mercilessly discarded, as if the Web Standard has been understood to be div+css. In fact, the table tag is not discarded, when the need to display the data content, the HTML structure built by the table tag is better than the layout of the DIV tag build, the table tag is still the most consistent HTML semantics when displaying the data.
The extra verbose code generated by the table page layout, along with the HTML style attributes mixed with it, has seriously affected the performance of the page, especially for large traffic sites, and the solution is to refactor the page based on Web standards. However, the misunderstanding of the web standards, resulting in the overall structure of the page div is too much use, and the table layout of the legacy of ideas, resulting in the page structure nesting too much. These still affect the overall performance of the page.
Therefore, to build a page with more semantic tags is the concept of web standards. In this concept to build the page should also try to streamline the code, so that the page code as much as possible to maintain the light, so that the browser more quickly rendered while also facilitate the future code maintenance.
The Web Standard is not a single standard, but a set of standards, including structure, performance, behavior three parts. The structure here does not refer to Div, but to the standardized language--xhtml, XML.
Clearly <strong/> Tags can be used to achieve bold style, why also use the <span/> tag with bold style to achieve it?