Cross platform solutions all share several issues that result in poor experiences:
Reimplementing platform UI
Poor reimplementaions of platform UI, such as navigation, that almost always looks subtley wrong or doesn't "feel" right in terms of interactivity. This also often lead to shipping a single platform's UI convention on every platform, for example Material on iOS or iOS patterns and conventions on Android.
Poor UX
An app's UI is more than just how it looks, just as important is how it feels, and if it fits in and feels at home as an app on the platform. Often cross platform solutions generate apps that have slightly "off" UX, such as sluggish interactivity(RN has this this issue), missing gestures(such as backswipe). In general many small cuts that deterioriate the user experience
Focus only on the visual
The visual representation of an app is only one part of the UI as mentioned above, an obvious other example is accessibility which is often lacking with cross platform tech, especially on iOS. I wrote a whole blog post about how Flutter Web fails[0] in this regard yesterday.
Binary size
By necessity cross platform solutions reinvent a lot of what the platform already provides which leads to larger binaries(performance is a feature).
Performance
Ionic for example, runs in a non-JIT(on iOS) enabled webview so can never match the performance of native. React Native runs a JS enging(again no JIT on iOS) which demands more from the device and uses more battery than native in my experience(performance is a feature).
In general, cross platform UI works by targetting a lowest common denominator of the platforms which naturally results in a worse experience.
Ionic is not Flutter. Flutter has to ship a ton of code to reimplement things Ionic can use right from the browser. Size increase is marginal with Ionic and Ionic can be used to build high lighthouse performance PWAs which Flutter Web cannot in its current state.
Ionic does use a JIT-ed webview. WKWebView is JIT'ed, but JavaScriptCore (which React Native uses) is not.
The rest of your points are subjective and we find Ionic apps, when designed well like any other app, have great performance and user ratings.
Hi Yesimahuman, I am really tired of seeing again and again the same myths being said about Ionic. Why not put an end to this by showing to the world scientific evidence?
I just created this issue for tracking such an effort and flutter strive for the same goal:
https://github.com/ionic-team/ionic-framework/issues/22417
Plus it would allow tracking/catching performance regressions
I think a better way to think of flutter web is flutter is using the web browser as a graphics layer to create a video game or desktop app, like SDL. It's not attempting to create an html web document.
Also nowadays the dominant computation platform of the world is mobile phones, with most of the world being Android and many with money being iOS. Desktop UIs like the web with custom screen reader & extensions & custom css mod and such are not the P0 priority. I would also imagine it's not the majority of people with these accessibility needs using it either. Desktops are the world of the office worker, middle aged person who's calcified into desktops or other power user types.
It would be hooking into iOS & Android standardized accessibility APIs. I'd imagine it executes far better there, because non-selectable text in UI elements are pretty much platform standard for mobile & desktop apps.
Furthermore in that light I'm guessing that flutter web & desktop are also P2 projects to the P1 flutter mobile projects, and android / material design is P0.
