Desktop features are noted as for compatibility reason these kinds of features are not possible for Browser
Desktop mode what's different:
Extras Bot builder desktop edition also allows for full offline bot development and creations obviously you can't run the bot offline but you can still build it.
Further more with the edition of Sockets you are able to make even larger bots that in desktop as you can spread the load
The way the engine works is with each change it will reconstruct all the paths to make it fast whenever code should be called however on a large scale bot this means its remapping a lot of old nodes with every change which can consume a huge amount of resources however once its mapped the resource usage will drop dramatically as it now has its map. This can be best seen in browser Where a bot is done with 80 nodes used 5GB of ram and took on average 6 minutes to reconstruct as well as the browser crashing however in desktop mode with sockets as each part was broken into a different window it was able to live time update with little to none lag.
As a reminder it's not a buy desktop version to unlock these features its fully free as well