[bcoughlan]

I think there is a case for both.

For many small or hobbyist projects it is not feasible to implement and test multiple UIs. If you have the resources and want a polished smooth experience then implement the UI layer natively.

That said we're not quite there with code sharing of non UI code between web, desktop, and mobile platforms. It's a niche that Kotlin is trying to fill but time will tell if it succeeds.

[hobofan]

Yes, if you want to do it professionally and keep up with the developments of a platform you will you have an ongoing cost for a whole product team for each of your target platforms. That additional cost ($500k-$1m per year per team) is very rarely worth the slight upside in usability, and there are probably many potential products that the team could work on that are more beneficial to the company.