In the cases I’m accustomed to the FX (anything inserted) is printed to the file. If there are time based effects that play beyond the end of the clip (tails) you can extend the clip length a little before bouncing to capture those in the bounce. But (in most cases I think) it renders the instrument with any insert FX.
Freeze gives you more options for the render, FX or not, tail length. Bounce just bounces and goes to unity on the new audio channel.
This all happens in a matter seconds. Probably less than two seconds.
It’s not a major deal but I seriously doubt it’s “less two seconds”. At any rate, the explanation was “what is it?”, not a determination of if everyone feels they need it. That’s for each person to decide, if having it is potentially useful or not.
Now if you can bounce perfectly (different?) sized / length audio clips from multiple midi clips across multiple tracks, with no dead space on the tracks where no midi clips were, in one go… in less than two seconds (not counting the actual render, just clicking around to start it), I’d be very surprised. I think it would require multiple trips to the stem render dialog to do what I described doing with a single action. Setting a different loop length every time.
At any rate, everyone kinda knows - what - it is now. Whether a person feels they’d benefit from it, personal decision.