I’d rather hear about a set of tradeoffs in these sorts of articles (performance was critical so we traded Y for X) than just bragging about one dimension of improvement.
I'd add that more often than not these performance impacts are not due to changes in programming languages/frameworks/libraries/whatever but because some architecture or algorithmic constraint is done under the scope of the migration.
Hence, I wonder how long it take a to build what is probably a medium size system when done by a team at Apple.
In my recent but limited experience of working on iOS apps, they do need any performance boost they can get anywhere. Coming to the Apple ecosystem (appstore connect, testflight, xcode etc) it's quite a shock on how slow it all is (using xcode on a Mac Mini M4 for development, and as for web updates/approvals etc I now understand the pain others have mentioned here).
That sounds like a phenomenal reduction in complexity!
What would make it inappropriate?
The Uplift War