Something that was talked about for a long time is getting closer to reality. F&O development will no longer require those huge VMs with SQL Server and everything. Instead, you’ll just install some VS extensions, connect to Dataverse, download F&O code and metadata and start developing. The runtime (web server, database) will be in cloud, which means that running and debugging your changes requires deploying them to an F&O environment in cloud.
Microsoft calls it a unified experience because it’s going in the direction used by other Dynamics products, it utilizes Power Platform and it provides tighter and easier integration between F&O and Power Platform.
Here is a brief introduction by Peter Villadsen: The Public Preview for the Unified Experience is live!. It contains links to the documentation with more details (which is also in preview).
I’m looking forward to the extra flexibility provided by the new solution. It should also have a positive impact on costs, because development teams won’t need so many powerful VMs (although details also also depends on things like Dataverse pricing). My recommendation is trying it and getting familiar with the new approach, but not hurrying with the real adoption, because changes are expected before it becomes generally available.