Sorry, I don't like it. For full disclosure, I am a casual user. I don't fly all the time, nor do I know anything about piloting.
There are two problems that I see with the application.
One, is that it is rather unpredictable in terms of where your ILS is going to be. You really can't set up for an approach until you are pretty close to your descent. Maybe the real world works in this way, but some idea as to where we are landing would be nice to have 100 km from where we are coming in. Yes, that could change based on weather, but please give us something to work with in the early stages.
The other is more technical. Seems like there are often problems with connecting to the sim. Not always. But it happens enough to be a hassle. If MSFS booted up faster, maybe this would be tolerable. But if you only have 90 minutes to play and you spend twenty of those minutes messing around between BATC and MSFS, the experience is not very pleasant.
So, from a layman perspective it is not a good look.