Some IoT systems don’t need business logic if there is only a backend implemented. However if there is backend along with some clients then there is a need to share common business logic (especially data models).

Had a situation a while back in a IoT project where there was a backend with two clients (Android, and desktop) written in Kotlin. Unfortunately Kotlin MPP couldn’t be used at the time since Android Studio doesn’t have official Kotlin MPP support, which meant the backend and the two clients had to be split into separate projects. This would cause some big pains when trying to manually synchronise data models between the projects. For instance every time the data models changed on the backend it would cause both clients to break, and some tedious/error prone work would ensue to fix the clients.