One of my users brought up a shortcoming of Teams (unless I am unaware) which was previously available in Skype. He will be on a meeting call with a group of people. Meanwhile, someone else not on the call is asking him to share his screen. He is not available to share his screen with anybody except the people he is on the current call with. A lot of times he will be on a call, but also troubleshooting a different issue not pertaining to that call and will want to share his screen with the other person not on the current call. Hopefully this makes sense.
Currently a call is required to share screen, it's not designed the way Skype was. I don't see this changing anytime soon. I would suggest checking microsoftteams.uservoice.com for a new entry requesting that Screen Sharing doens't require a call and try to get people to vote for it. I know I would cause the way it works now isn't ideal.
Yes it does. From a technical standpoint, it's making a call for you and starting screenshare, that's all it's doing. It still requires a "Call". I know you don't have to play Hello can you hear me game before screen share now :P.