As far as I can tell, all of these assistants are designed to work from a central hub, desktop, or server. The Sapphire Framework is specifically designed to work on mobile devices without the need of any network connectivity.
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Originally, this was supposed to be in conjunction with Mycroft.AI so that you could run Mycroft on Android. However there are significant differences between a Linux system and Android, which caused me to change the focus of development.
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A secondary reason I focused on mobile devices (and hence, my own project) over server based devices is that there are many users globally who only own a single computer, and that would be their mobile device. I wanted to develop a tool that could be used by the broadest number of people, so hence I started the Sapphire Framework project
I'd ask the projects that you intend to consume the service what they could handle. I've heard that a straight GPL doesn't preclude it being offered as a SaaS for profit, and there are a number of projects that have changed the license because they've been hit with competing companies doing that, and then not putting up the changes they've made because selling a hosted service avoids the requirements that packaging it for download makes necessary. It seems like they move to an AGPL in those cases.
https://www.whitesourcesoftware.com/resources/blog/the-saas-loophole-in-gpl-open-source-licenses/