Software update groups provide you with an effective method to organize software updates in your environment. Software update group consists of multiple software updates (metadata Only) .You can manually add software updates to a software update group or automatically add software updates to a software update group by using an ADR.
One of the major advantage using software update group is ,easier to track the compliance status using reports or console method for multiple updates that you have deployed and delegate software update administration (You can set a security scope for each software update group).
If you have multiple software update groups to deploy to multiple collections as part of monthly patching ,it would be difficult to do it via console .why is it difficult ? well ,the user interface takes very long time (depends on the number of updates in each update group) to process the updates in each software update group ,validate and deploy to collection with some settings like available date,deadline date/time ,reboot settings,download settings etc. If you have already doing it from the console with user interface ,you really need to look at other methods like tools or powershell script to save your time .