I don’t think that premise of “native UI for anything that needs polish” is true these days.
Canonical the company behind Ubuntu have said for some time now that all future app UIs of theirs would be done in Flutter starting with the very first thing people see the installation process.
Google just rewrote Google Earth’s UI in Flutter.
BMW are doing all of their in-car entertainment systems in Flutter.
Are any of those better than the alternative, or just cheaper?
I suppose if the alternative is “this only exists on one platform” or “this doesn’t exist at all” then maybe, but I find it a bit sad how keen we are as a profession to accept compromise and mediocrity to save developer time and expense.
2/3 of those examples had no requirements for cross platform and still chose it anyways. Additionally all 3 of those examples decided to take what they already had with native and decided to rewrite it because of the benefits.
I’m saying the “gap” between Flutter and native in this case is much much much smaller than you seem to think it is. Quite a bit has changed there in the past year or two.
That isn’t my opinion but that was the result of many major and very competent teams coming to that conclusion and putting their money where their mouth is in order to substantiate the claim.
Two of the examples mention are platform providers. If they standardize on flutter as their native UI, that’s fine and they are following my suggestion. If they port a BMW app from my dashboard to iOS / Android, I’m 99% sure you’ll see the issues I mentioned.
Google earth is fine, but doesn’t feel native. I think that’s fine for some apps (games mostly).
Welcome screen was a popover on iPhone (only available on iPads, should be a sheet on iPhone), with rounded non standard button and non standard horizontal lines.
“Signed in as” toast wasn’t designed for iOS rounded bottom and “swipe up” bar leaving ugly stripe.
Sheet easing is off, and FPS stutter.
No swipe from left to go back support.
Non standard animations all over. Visible FPS issues (on newest HW)
I could go on and on. Feels like an android app running in an emulator.
You asked how it doesn’t feel native. Using a design system from a different platform, and not complying with the interface guidelines of the current platform, is a big part of not feeling native.
And the frame drops and lack of system gestures, and lack of standard nav stack are major infractions on usability outside of design.
Canonical the company behind Ubuntu have said for some time now that all future app UIs of theirs would be done in Flutter starting with the very first thing people see the installation process.
Google just rewrote Google Earth’s UI in Flutter.
BMW are doing all of their in-car entertainment systems in Flutter.