I actually REALLY like this feature. It gives you a notification to tell you that they are in an instance. If it didn't then I could see it not being a good thing. It really isn't all that different from Deadly Boss mods in WoW.
Benefits:
 1) Helps you with immersion because you don't have distractions from your story.
2) Helps you to not be distracted in boss fights and battles.Â
3) You have less chance of missing a /tell. I can't tell you how many times I was so involved with a fight that I missed someone talking to me in other games.
Negatives:
1) You have to wait til your friend isn't busy to talk to them.
Benefits:
 1) Helps you with immersion because you don't have distractions from your story.
2) Helps you to not be distracted in boss fights and battles.Â
3) You have less chance of missing a /tell. I can't tell you how many times I was so involved with a fight that I missed someone talking to me in other games.
Negatives:
1) You have to wait til your friend isn't busy to talk to them.