I dont understand why a absolutely positioned layout isnt logical and browser safe
One of the most important aspects of web design (regardless of device) is to maintain the flow of the document.
In simple terms that means that one element can follow the next and you don't have to do anything special to make that happen. If you want another paragraph you just add the text and there it is under the paragraph above. If you then want to remove the first paragraph you just delete it and the content underneath just rises up into position all on its own. If you narrow the browser window all paragraphs flow together and push down the page without overlapping.
Now imagine you are absolutely placing those paragraphs. If you want to place a second paragraph you have to absolutely place it below the other one at an exact height or it will overlap. However if the content changes, the text is resized, or the window narrowed then the content overlaps because all elements are removed from the flow and do not care about anything else.
If you remove one of the absolute paragraphs you leave a hole in the page and the other content does not fill the space. If you want to add more paragraphs you have to position them at the bottom but you don't actually know where the bottom is.
As you can see its a nightmare to manage at every stage unless you have the simplest layout. A 2 column absolute layout is not that bad and can be maintained but you can never have a footer or put content at below both columns. In this case it would just make sense to float them (or use display:table-cell for ie8+ if needed) and avoid the issue altogether.
Floats, although removed from the flow , can be cleared and thus thus flow of the page is maintained. You should always take the route of least resistance and when you code with the flow of the page then in most cases you don;t need to do anything special as content takes care of itself. Just a few margins and tweaks and everything falls into position.
That doesn't mean avoid absolute positioning as you can use it in controlled situations to good effect. e.g. within a fixed height container such as a header banner you could absolutely place a logo in the top corner easier than floating especially if you want it on top of something else.
There are always special cases but in the main you want to keep everything in the flow of the document (one element follows another naturally).