The company I work for has started looking into Jira Assets (formally insights)
Some of the teams are front facing with customers and the mobile app is easier for most of these interactions with the customers and the assets.
Is there any plan / roadmap for the Jira app to include assets?
Depends what you want to be able to do.
If you want to be able to go into the schemas and create objects directly, I doubt it is coming anytime soon.
But if you want to view, or search for assets from an Assets Object custom field, or create/modify objects via fields in jira that interact with the objects via automation.....all of that is currently possible.