It's a good distinction. Unfortunately the term "interrupt" here is a bit overloaded since you definitely get some real assholes interrupting for nefarious purposes. "Cooperative overlap" often gets used to describe this non-competitive, overlapping communication style (though I think it's not quite explicit enough for an audience who spends a lot of time thinking about communication protocols etc.)
Exactly. Interrupting when you want to talk but being unwilling to yield in return, or unwilling to let them continue if they insist, isn’t an efficient conversational technique, it’s just bulldozing.
I also draw a distinction between interrupting (and then monopolising the floor) and interjecting with a quick addition before handing back to the speaker.