It is useful to know if the project you are creating touches at any point any restricted area
Have you tried the Airmap plug-in on the DroneDeploy App Market? I would also suggest Atmosoar Windsock for other important location flight data.
I use this websites KMZ to check, but I 100% agree with you that it would be good to see the lines. I use the apps Michael mentioned and I agree they are helpful!