I just downloaded version 4.1.8 of Oracles VirtualBox Manager and was delighted to see that it offered to download the extension pack and install it for me. That was always a bothersome additional step that needed to be done and bringing that into VirtualBox improves the usability of the product. Also, this encourages me to stay more current with updates, since the update process involves "manually" downloading and installing one file instead of two.
Nice improvement and an "Attaboy" to the VirtualBox developers!