The main point here is to gain improved resolution on text where it's quite noticeable going from 140 PPI to 280 PPI - many developers will appreciate it.
It should be fine for the kind of work you're doing though, are you using tools that don't support DPI scaling?
I dunno, in my experience going from 1080p to 4K is a huge benefit for photos as well. While I wouldn't necessarily notice the extra details when looking at a photo from a distance, when I see the 4K next to the 1080p displaying the same photo it is noticeably more "realistic" somehow. Considering that even phone cameras take 12MP+ pictures, that extra detail has to count for something. For me pretty much everything looks noticeably better on a 4K display. Granted I'm slightly under 30 but I do wear glasses, so I dunno how much eyesight affects things.
I leveraged scaling and kind of played with different options of it.
For developers working with proportional code - unless you have super sharp eyes to scale your Sublime Editor to sub-1mm characters - i don't see it making much difference.
I physically feel comfortable with a text character of a certain minimal size.
Beyond 4k it really doesn't matter how many pixels or colors are used to render the font or image on 15" screen. Making it too tiny or super-true-color-ish doesn't make much difference on a laptop screen that typically only used for "temporary" on-the-road work.
It's about being able to use more pixels to render things like curves and serifs in fonts mainly - things that subpixel hinting attempted to address on lower DPI displays can now be done much better and without the blur tradeoff by using more pixels. At the very same size, fonts look noticeably better because more pixels can go into those tiny rounded edges.
I do high definition photography (think gigapixel panoramas) and editing anything like that on 3840x2160 laptop (high end laptop) is a suffering.
I always looking forward to get back to my 32" monitor.