Withings decision to make Apple Health sync a Withings+ feature goes against the App Store Guidelines

Writing to HealthKit is a built in capability. This should be the end of it clearly and simple. 4.10ASR & NR Monetizing Built-In Capabilities You may not monetize built-in capabilities provided by the hardware or operating system, such as Push Notifications, the camera, or the gyroscope; or Apple services and technologies, such as Apple Music access, iCloud storage, or Screen Time APIs.