If you start talking about SQL Server Service Packs, Cumulative Updates and Hotfixes, then you need authorities in both Windows and SQL Server. This also applies to Security Updates that affect SQL Server - fortunately on average we only get one of these each year as most Security Updates do not affect SQL Server.

However, most sites will apply SQL Server updates separately to Windows updates and often use a different account for each type of update. It is considered best practice to run these types of update separately.