I love diesels, but I don't own one. There is no cost advantage. Although reliability isn't bad, eventually they all need very expensive repairs. Nothing is cheap about repairing a diesel. The initial cost is much higher also. There advantages are high torque and the fact that diesel fuel has more energy then gas. As far as the cost of diesel, there is no good reason it is not cheaper then gas.
On AS, we make modern chainsaws sound more complicated then they are. In truth, they are marvels of simplicity. There are no valves or complicated fuel systems. The only moving parts are the crankshaft, connecting rod and piston. Why would we want to screw with that. Even if someone did come up with a functioning and not smelly diesel chainsaw, there is no way it would be cheaper, lighter, and more efficient than a gas chainsaw.
There's one good reason, because we are humans and humans love accomplishing what "can't be done".
Why do guys like dorking around with stock vehicles? they work when you buy them new..but..any possible coneivable mod has been done and will be done. Engine swaps, gas to diesel, diesel to gas, eityher to battery electric, to propane, to natgas, to woodgas, to..anitmatter drive!
Know what I am saying? Whoever built this prototuype, which we have not seen yet, and have no specs for or details or pics or vids, had a mental itch that needed scratching, and that is more than reason enough to give it a whack.
Would there be a market?
well..put me down as a good maybe on that. Why? We stockpile thousands of gallons of diesel here, but gasoline requires me to drive to the no E station and get cans, that's why. If there was a reliable functional diesel saw that was as good as say saws made even 20 years ago..I'm in for at least one, to try it out (given I could afford it at the time it hit market of course)
I am at 4.5 cords and counting with my battery electric saw. Lithium Ion tech tipped the scales into the "practical for some cutting jobs" area there (along with a TON of other applications, a serious game changer). That is relatively recent historically speaking. Previous tech, although it worked, was lacking, NiCad and NiMH just not suitable.
Vehicles, carbs work, simpler (somewhat, kinda sorta), cheaper, but..they just don't have the combination of mileage/power/cleanliness of FI.
Innovation and tinkering is what makes us humans really, if we ever hit a plateau where "nothing more needs to be done, it is as good as it gets"..well...I just don't think we will ever see that.
Anyway, let's see what the inventor/builder has first...whether he was just farting around or actually came up with some spiffy new ideas.