NicolasKheirallah
Thank you very much for this insight. Always good to share our experiences. In my company (~40.000 people) we run a heavily personalized intranet homepage with lots of audience-targeted web parts - all done with standard SharePoint. It's the default homepage in our browsers and integrated into Teams via the custom app route. On mobile everything is perfectly accessible and readable.
At the moment I'm not seeing the added value of Viva Connections. The adaptive cards in the dashboard are nice but I guess you could just use the dashboard like a normal web part without having to roll out the Viva Connections Teams integration if you wanted to use these cards. The mobile experience is a tiny bit more sleek than the (still very usable) responsive view of the intranet - but this comes at the huge cost of substituting the intranet homepage with the Viva terrible trio of dashboard, feed and resources which just doesn't work as well as a well-thought-out intranet homepage (which usually have different main focuses unique to each company). I also wouldn't like to be the one having to explain to users why "the intranet" looks and works different on their mobile devices than on their notebooks and why they can't easily see the same personalized content on mobile or why they can/need to jump from the Viva experience to the "real" intranet homepage experience. Adding to that the Viva Connections feed - from a Corporate Communications perspective - is clearly inferior to a news web part if you want to make sure that the right news get to the right people and retain some control over the newsfeed.
I'm happy that it worked out for your customers, but I'm wondering: Did they have a good personalized home site that's also integrated into Teams before Viva? Did they still see Viva Connections as a step forward then? Unfortunately Microsoft doesn't really promote the Intelligent Intranet very well but I believe that if you manage to build a good iteration of it yourself, then Viva is more of a step backwards.