It sounds like you have a great filtration system.
Being familiar with the basics for a furnace operation and typical failures, I do not understand how a top notch fibrillation system could save the burner assembly from failure. The filtration system keeps the heat exchanger much cleaner on the outside and may improve heat transfer, but does little to protect the parts of the furnace that typically fail.
And I do not understand how a thermostat will save on heating fuel. To keep a home at 70 degrees (or whatever your desired temp) it takes a certain amount of fuel, which means the furnace has to do the job and burn the fuel to do it. The only way it could save fuel is automatically lowering the temp on certain occasions, such as night time. Many have less expensive thermostats that already do this, we do it manually as we go to bed and then get up in the morning.
Dirt can be tobacco smoke and the like, which is like tar, even worse as it clogs up the A/C fins above the furnace. And even after professional cleaning builds up to the point where professional cleaning just cannot help.
A HEPA filter can get rid of much dirt except for it reduces air flow and does not get rid of the micro particles.
Whereas a Powered Filter, unlike the HEPA filter actually allows greater air flow than typical pleated ones, does catch the micro particles onto the pads, which are then thrown away.
2) Not only this, but the Powered filter reduces the humidity. And as you know, humid air takes much more energy to heat/cool.
So, better air flow, lowered humidity means the furnace A/C system is not coming on as often as it normally would.
3) As for a Wi-Fi Thermostat, like the Nest 3rd generation builds up the heat/cooling slowly and not all at once as most do. And is the most efficient as you know. Not only this but the Wi-Fi accesses the weather stations, particularly the outdoor humidity and wind. So, the thermostat knows what it will be facing as no house is sealed ultimately. High wind, high outdoor humidity will need a greater attack initially. Then after the initial humidity is reduced a more efficient profile can be used.
4) Synergistic effect: The lowered humidity, lowered micro dirt tar, and increased flow of around 30% means increased efficiency and less wear. Then the smart 3rd Generation thermostat takes it to the next level.
And just so you know I'm not whistling dixie. We felt the difference with the Powered filter immediately.
Our skin cleaned up and congestion was much reduced as we are older.
We heard the difference as the intake vents started to sing and had to be adjusted. Our furnace used to rattle after being on for over 8 minutes. We noted that with the 3rd Generation thermostat we almost never hear that rattle.
We see the difference with the numbers of hours used. And less hours used= less wear and tear.
And yes, I anticipated the push back. And I appreciate it.