Also comes back to the thing of "products end up modelling the organisational structure". If it's painless to create new internal products within your company

Also comes back to the thing of "products end up modelling the organisational structure". If it's painless to create new internal products within your company & there is operational support for it, you're more likely to spin up a sister "EmailNotificationService" alongside "SmsNotificationService". If you have to jump through hoops to get sign-off and business cases etc and eitherways it's the same team responsible for both, people are more likely to say "let's just put the functionality in here"