Try a little test
take your computer monitor, put a couple of sheets of A4 over it, so the screen is completely covered. Now cut a rectangluar hole in the paper, about 3 inches by 2, somewhere near the centre of the screen.
Now try and do any useful work in that area.
Congratulations! you're now experiencing "smartphone" computing.Although this phone may allow you to have "... many windows open at once ..." in practice it can't even manage one, decent sized one. Of course, you could always use the smartphone (or tablet? whatever!) outside. Then the number of open windows becomes immaterial - as none of them will have any visible contents showing in any conditions brighter than darkening twilight..
To further enhance the smartphone experience, put on a pair of boxing gloves and try typing. Excellent, you now know what it is like to use the keyboards on these matchbox-sized devices.
While the technology is impressive - what with all the gigabytes and megahertz (and most of all the price), in practice it falls far short of anything that could be described as "smart" or bear any resemblance to tablet computers (which I thought had died a faddish death sometime around 2003, oh well) in the usability stakes. While you may get lots of geek-points from all your nerdy friends for having the latest tech - well, for a few weeks anyway, it's really nothing more than a phone: press buttons, talk to people. Trying to use it for anything else is great for the marketing box-tickers, but falls short in practice.
 except, possibly listening to music.