That definitely works for some apps, but unfortunately, I think it doesn’t quite work for certain apps and situations.
For example, in Instagram, if you only want some notifications, holding down the notification only lets you turn off all the notifications. You have hunt for the notification settings in the app if you only want to turn off certain notifications.
And the Facebook app has two separate pages of notifications: one for app settings and one for account settings. At least to me, I think it’s a pain to find the right setting to turn off.
I’m hopeful that things will get better in the future though.