Low-latency UIs that respect user input are amazing. They're just quite rare these days. I guarantee the difference is noticeable and makes a difference—look at how everyone liked (and still likes) the UI smoothness and low UI latency of iOS, for example, and iOS, though probably the current front runner on this front for popular operating systems, is just so-so at it.

I guess if my principle is that I like my computer to respond quickly and accurately to my input then yeah, I dislike webtech junk on principle.

[EDIT] as far as it not mattering, everyone I know, including plenty of non-techies, who has used Google Docs hates it, due to the UI lag. Typing with that large a delay between keypress and the letter appearing sucks. They may use it anyway because they have to, but they all complain about how laggy the UI is, responding to clicks and keypresses.

Google Docs on what device? Their iOS apps are famously bad on slower iPads (like the original Air) but the website with a correctly configured browser on a reasonably-specced laptop or desktop is very responsive, once it loads. Of course, I'm not a fan of it myself, but the input lag isn't the reason.

Another, maybe more appropriate, comparison for UI lag might be between VisualStudio Code and Sublime Text. VSCode is based on Electron and though it is well optimized and a fine editor, I can feel the lag when I use it to edit code. One the other hand, ST is native and editing any text is super smooth, even files that are much too large as to be reasonably edited.

I use it on the desktop too. And it is slow. Slow to start, slow to load channel data. Slow to appear after alt-tab, and so on.

I think it is because it expires caches left and right, loses track of events, or I have no idea what else could be going on on a PC with 16GB RAM (plenty of it free) and stable Internet connection.

> I've been using Slack on the desktop daily since the alpha version. I've never found it to have UI lag.

Try telegram on desktop and compare the UI performance. Slack definitely has UI lag. Not nearly as bad as Teams though.

Easy way to demonstrate the jank: switch tabs quickly on desktop Slack. The new views take a nonzero amount of time to render. Do the same thing on Sublime Text 3. Even big files with lots of syntax highlighting load nearly instantly, or at the least, much much faster.