I can only speak from my limited experience, but for the last 2 years or so that my team has used MM, there's been no radishworks/mm sponsored or developed application. Be that as it may, there are some apps that have had MM connectivity added to it, but it's all based on having an internet connection to "attach" to the database to view mission status and job assignments. Since sarapp was a program that already existed AND was mostly web based, it seemed logical for them to work with MM if they could.
The flexibility of the SaaS model is a way to rapidly deploy and update an offering. MM leverages this capacity to the SAR vertical very well since it can be used by most devices that have web access regardless of OS and most browsers can use it effectively. Yes having a standalone (albeit network capable) app could be nice for IT coordinators, it's impractical as a "free" offering when considering developing an app for desktop and mobile use that also works on multiple operating systems. For now I'd say we're lucky to have what we do. Having it browser based also allows for virtually instant expansion of the coordination effort.
Most of this is purely based on my opinion and your opinion may vary.