Congrats on a very nice Bimmer !
What color is it?
If you decide to Opti-Coat it, are you going to want to have all the paint defects removed before the coating? If not, they are always going to show, and you cannot get to them without removing the Opti-Coat and then starting all over again.
To have a good Detailer remove all the paint defects and Opti-Coat a vehicle can cost several hundred dollars.
If you are not driving it much anyway, perhaps just wait and see how the paint looks at Lease Turn In time and maybe you can have a good Detailer go over the paint to bring it back to new or better than new, and just turn the car in?
I dont think that BMW is going to care much how the paint looks at Lease Turn In, unless it is severely scratched, etc.. Review the Lease Agreement, they do give you so much leeway even in how many dings it has.
The answer is Yes - a vehicle that has been Opti-Coated/Guarded, will definitely be easier to wash, because stuff doesn't stick to to the coating as easily, even when the paint has been waxed or sealed, etc..
Good luck with your research !
Dan F