Are you from NYC or Great Britain?
(Just kidding! I know you're just being polite.) 
I still want a Black Cat (Made in Gemany) light…
One of my favorite bicycle headlight brand back in 2007.
2015 CatEye Volt 6000 6000lm COB @$800
I never said all lights overcharge with their onboard charging circuit, but too many do. If you check the cells as you did, you can verify the charging integrity. Otherwise you are playing russian roulette with your batteries.
I just think it’s hella convenient if you can just plug it in like a phone, vs doing the organ transplant thing all the time, wearing out the ano, O-rings, etc., even if only marginally.
Simple to check it once to see how it does, vs the usual paranoia (eg, “russian roulette”, etc.) about it.
I just don’t get that kneejerk aversion to onboard charging, yet I keep seeing it over and over and over, people bellyaching about how onboard charging is “unreliable”, etc. Seriously, it’s like a a little kid saying how he hates broccoli. “Have you ever tasted it?” “No, but I hate it anyway.”
Hell, I used to just pull out a cable and charge my ’20 from the charging ports on the bus when I’d take it. Or plug it into a usb port at work. Anywhere I needed or just wanted a top-off. Convenient as Hell…
Once, that’s all it takes. Charge the cell, check the voltage, one and done. Simple. Really can’t get any simpler than that.
Or micro vs C. Oh, boo-hoo-f’n-hoo. I gotta carry a whoooole ’nother cable. The crosses I have to bear…
Thank B’harni (pbuh!) we’re beyond the days of various’n’sundry wall-warts, each with its own voltage, current, plug size, and ± vs ∓, etc.
And of course, one demands micro but not C, and another demands C but not micro. And another wants both. And someone else demands no charging ports at all. And then the magnetic-only crowd chimes in…
:weary:
“I just think it’s hella convenient……”
Ya just wait until ya forgot your C-cable in the middle of no where in a turd-world situation. And yer desperate for a charge.
Then ya ask to borrow a cable only to find out everyone has only micros or lightnings.
BWWWWAAAAHHAHAHA!!!…. THEN you’ll remember Notta’s crazy cackle. 
PS. I think onboard charging comes with almost every new flash I buy going forward. Or it could be a deal killer.
Or, you’ll be in the jungle somewhere with your micro-usb doodad looking for a charge, and everyone else got only C and lightning.
“What?? Micro? Pfffft… that’s so 1980s.”
Sure ...I want color changing tint and high cri .....and want the ano to color change at will as well .
Shake to charge.
I agree it can be convenient to use onboard charging, and it pays to know…by checking with a meter…which lights can reliably do so. The issue exists however, that most people just assume the flashlight will properly charge a light, just because usb or usb-c charging ports exist. On many lights this assumption is wrong and can reduce the life of batteries at best. For an EDC light it might surely be worth the effort, but in my case, with a half dozen high quality chargers, hundreds of batteries. and plastic cases for carrying them, it is just easier and safer to just carry spare cells. It is extremely rare that I will use a light to charge a battery, but I do have a few that I verified sufficiently to trust for charging. My most used charger the XTAR VC-8 has the added benefit of displaying the mah introduced in the cell which aids in monitoring battery health. For a beginner in vaping or light collecting, I can surely see the need for on board charging, but after a while, it is easier to just charge 8 cells or more at once. I have had three 8 cell chargers fully loaded at one time, usually when I bought a bunch of new batteries, and also decided to top off older ones.