Native apps (including those delivered using technologies such as Uno) offer a richer user experience with better performance and a more native look and feel. Blazor currently is an incubator technology that suffers from slow initial download and still relies on all the cludges that we've come to rely on for the web (html, css etc)
Why bother with building iOS, Android and win 10 app when can active similar features with a single blazor wasm progressive app?