Only optional writing of extended color information into description
Without an option to prevent usage of description field, color information ("BC2-Color: ...") is also shared with participants of meetings for example. I prefer using description field for information that participants understand (agenda, ...). Only BC2 will not display it, Outlook, Nextcloud and other mobile apps are showing it.
Without the option there is also no way to prevent colors being synced when calendars are shared. Even if sync tool has such option (e.g. DAVx5) BC2 uses information in description and ignores empty native color information. Example is when you want to have your partners calendar on your phone but she/he is using different event colors and you want to see it just in one color.
When using NextCloud and CaldDAV sync there is not even a need for additional color information in description. Sync of additional event colors works perfect without it.
Yes, important option. Don't want that participants of meetings can see how I "rate" the meeting ;-)