You asked a couple of questions in your post:
Is there any use for page development [using HTML5]?
Yes
Using the new semantic network, you get semantics. You give meaning to your data, which can then be done to do wonderful things.
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HTML , HTML , , ( - ). (: FF, Safari, Opera, Chrome) , , HTML5:
section, header, footer, nav, article
{
display: block;
}
, , , * cough * IE * cough * ( , IE dev - HTML).
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...
HTML5 , - HTML5.