For a newsletters management page, when the user subscribes to a newsletter and clicks on the relative icon to subscribe (in this case an empty circle), is it necessary to push a pop up message confirming the subscription like “you have successfully subscribed to 1 newsletter” or a simple animation (the empty circle will be replaced from a loading one and finally with a checked circle) could be enough to communicate to the user that he correctly subscribed to the newsletter?
I think the alert would slow down the action of the user to subscribe also to other newsletters, since he would have to wait for the alert to disappear or he could still subscribe to others NL but with a list of confirmation alerts popping up on the screen.
I was thinking to show alerts just in case of error