That's a very arrogant attitude, if I may say so.
You don't have to switch if you don't want to... you can stay in the stone-age of web design if you would prefer. But there are many benefits to using XHTML over HTML.
HTML is rapidly being replaced by XHTML. The differences are very minor, but the results of switching can be worth the effort. The primary benefit is that XHTML is more widely accepted in non "computer" devices like cell phone, palm devices and other scaled down browsers. This is commonly called portability between devices.
XHTML is also said to be extensible, which is the fancy way of saying the new tags can be added without a new document type declaration.
XHTML is fundamentally different from HTML, despite looking very similar.
- XHTML is XML, which means that the syntax rules are slightly different.
- There are things you can do in XHTML which you cannot do in HTML.
- There are things you can do in HTML which you cannot do in XHTML.
- There are differences concerning CSS.
XHTML 1.0 was created shortly after HTML 4.01 to help the transition of hypertext to a new generation of mark-up languages for text. XHTML 1.1 is an additional step toward a more flexible version of hypertext with the full benefits of XML architecture and integration of different technologies.
XHTML is also easier to maintain
XML syntax rules are far more rigorous than HTML. As a result, XHTML makes authors work more precisely, having to address issues such as:
- all elements and attribute names must appear in lower case
- all attribute values must be quoted
- non-Empty Elements require a closing tag
- empty elements are terminated using a space and a trailing slash
- no attribute minimization is allowed
- in strict XHTML, all inline elements must be contained in a block element
Yes, HTML is as valuable as XHTML in a daily usage. But XHTML has several important benefits. The weight of these benefits has to be evaluated in the context of your project: Use the right tool for the right job.
For a Web designer, starting to use XHTML will be helpful in some circumstances and will certainly help you to smoothly negotiate the future. XHTML gives a wonderful opportunity to learn about XML languages and their possibilities without having to learn new semantics because you’re working with familiar tags and attributes.