The advantage of this is that if the door is already open, the car won't close it as you approach the driveway, nor will it open a closed door when it should be trying to close it. The other advantage is that it could get people to buy the MyQ hardware...if they didn't have a subscription fee. By charging for something with a minor advantage, they are cutting of their biggest selling point.
Another advantage is that it will get rid of the limit of three devices. But it means removing my current garage door from Homelink, and adding it to MyQ so I get one more entry. I have no direct control over the hardware for the others, so adding MyQ to them is not an option. I have two more potential ones that I'd add to the menu, but neither has or will have the MyQ hardware.
It also has the advantage that the car will know if it's successful. It would be nice not to have to press the screen when it doesn't work, so currently, it's a matter of living with a greater chance of having to press the screen manually, or dealing with having to be closer when it's activated, and possibly having to wait for a gate or door to open.
Hopefully, somebody from Chamberlain will have the common sense to realize that there are millions of potential Tesla customers who would go out and buy the MyQ hardware instead of the Homelink hardware, if they didn't have to pay for a subscription. But I doubt that more than a small fraction of them would pay for the subscription, when they could spend slightly more on Homelink for a lifetime solution.