@fabioconte  FHD+ is simply because the newer XPS 13s have a 16:10 aspect ratio display rather than the standard FHD 16:9.  So think of it as "tall FHD".  The plus doesn't mean it's sharper; it's just bigger, specifically 1920x1200 rather than 1920x1080.

In terms of UHD, I will say that when I ordered an XPS 15 9530 back in 2013, I chose the 3200x1800 option (full UHD wasn't available on that model) because I figured it made sense to be forward-looking, etc.  When I just bought a new laptop a few months ago, I went with FHD instead of UHD, even though cost wasn't a factor for me at all.  I think touchscreens are useless on non-2-in-1 systems since it's tiresome to hold your arm up in the air to use them, so I never do (and I really wonder why anybody offers them, but whatever).  I also don't like glossy displays if I can avoid them.  And then as you say, UHD displays impose a non-trivial penalty on battery life, and they also make the system a bit thicker and heavier.  I finally told myself that it was pointless for me to spend MORE money for a bunch of things I either didn't care about or actively didn't want.

In fairness, I will say that I use my system in a docking station a fair amount of the time, so I don't use the built-in display as much as others might in the first place.  And I freely admit that the "Retina display" high pixel density experience is quite nice -- but only when it works.  Windows has been getting better here, but I still find that I have some applications that just don't handle display scaling very well at all, and in that case they can actually end up looking WORSE than they would if I'd just been using an FHD display with 100% scaling.  So here again I had to ask myself whether having print-quality text when things worked was worth the aggravation of other applications looking terrible because they don't support display scaling properly.

So for me, the only upside to UHD -- some applications looking incredible -- came with the risk that other applications would look even worse than they would have otherwise, and then there were a bunch of other downsides that would have existed even if all of my applications scaled perfectly.

I have no regrets opting for FHD on my new laptop.

Forgot to include a link to the page with the viewing chart I was talking about.  Here it is: https://www.rgb.com/display-size-resolution-and-ideal-viewing-distance

Thank you for the excellent reply very helpful 

@fabioconte  one last note with respect to UHD streaming.  On a 13" display, even FHD resolution (FHD+, excuse me) has quite a high pixel density, so I seriously question whether the extra resolution of UHD would make a difference.  Take a look at the chart on this page.  It doesn't go as low as 13", but as you can see, even on a 24" display, you need to be only about 3 feet away for the benefits of 4K to even start being noticeable.  That said, it's also true some streaming sources only provide HDR as part of their UHD streams.  The benefits of HDR are huge and absolutely noticeable regardless of display size because HDR focuses on contrast, brightness, and color gamut.  But the catch there is that you need a display/TV that's capable of reproducing a wide color gamut and high peak brightness in order to really see that difference, and right now even desktop displays don't really get bright enough to really show off HDR.  On the laptop side, some higher-end laptop displays can cover the color gamut aspect nicely, but they're even farther behind desktop displays on brightness because they have power budgets to worry about.  And that's before even considering the reality that getting HDR working properly on a Windows PC is still a huge chore.  It messes up the appearance of any SDR content you might be viewing at the same time, application support is still all over the place, and even some streaming sources that support HDR might only deliver it to streaming boxes and TVs rather than PC apps or conventional browsers.

So, bottom line: When it comes to streaming, the extra resolution of UHD content viewed on a UHD display is highly unlikely to be noticeable on a 13" display.  If the provider you're streaming from has a system where the only way to get HDR is to use a system that also supports UHD, then that might be worth considering, but even there I would argue that it isn't, simply because even if you can get HDR working somewhat well in Windows, today's laptop displays just don't do justice to HDR.  If you want to see proper HDR, you need a decently high-end TV, because even the majority of TVs that claim HDR support don't render it especially well.  But at least there you don't have to deal with jumping through setup hoops like you do with Windows.  It just works.

Thank you !!!