Viva is a brand for employee engagement. It seems such a hodge podge of different things. Maybe it will come togheter.
Viva Connections -- has not made any sense to me. Do some people access Sharepoint through the Teams app? I guess if there was a quick thing to look up. I would say the same for editing documents, do people edit documents IN the Teams window? It seems like Microsoft has some use case where people spend their entire day inside the Teams client. I would rather keep Teams for the "glue" - chat and meetings.
Viva Insights - Free version is Limited to a few personal features that end up being more annoying than useful; much more extensive version paid for large organizations
Viva Topics - Paid only, and expensive. Is anyone subscribing to it?
Viva Engage - it is unclear if Viva Engage and Yammer are equivalent, I think yes. The stories and storylines are being added to Yammer and Engage is just the icon in Teams (can someone confirm?)
Viva Learning - the free option is very limited. I have had a hard time understanding what is free. I like the idea of some accessible on the job training.