This actually is kind of an "obvious" idea once you think about it considering that this is exactly what my oil company does. They monitor my oil tank and come fill it when its about half empty and leave the bill on the door and you can optionally keep a credit card on file for autopay if you want.
The convenience factor is really on point, I no longer think about oil at all, its always taken care of.
The company I work for does this :) We use cellular & network connections to do remote monitoring of tanks. It can be very valuable service for fuel delivery companies, since they can fill up on an as needed basis rather than driving out to a location only to find they only need to top up 5% of the tank.
I did that for years (called around) and potentially paying a small markup is totally worth the price of not having to think about oil. Plus, they gave me $150 off for signing up.
The convenience factor is really on point, I no longer think about oil at all, its always taken care of.