I got started with kb training through martial arts over a decade ago [...] I pulled 150 kg (330 lbs) as a PR on my first ever serious DL session [...]
This reinforces what Matt wrote and most of us know already; anyone who dismisses the kettlebell as a strength builder simply doesnt know what he/she is talking about.
My experience is that, using only barbells, healthy guys under 50yo can deadlift 150kg in 3-6 months.
Using barbells, you did it in 10+ years. Yes, you may have been able to pull 150 before this time had you tried - but not after 3-6 months of kettlebells.
In other words, everything works if you put enough time and effort into it, the question is what's optimal. Kettlebells are
not optimal for the development of strength, barbells are.
Kettlebells offer other benefits, however. With swings etc they also develop cardiovascular fitness - but not as much as running would. With snatches and goblet squats they develop joint mobility - but not as much as doing yoga would.
So if you want strength, use barbells.
If you want endurance, run.
If you want mobility, do yoga.
If you want a bit of each, use kettlebells.
As well, kettlebells are convenient. They're small and most of us can get away with just having 3 of them of about 4kg apart - one for presses, one for squats, one for swings or deadlifts, and of course you can progress through them over time, but you'd still rarely have to buy a new one more often than annually, and would end up with at most 8 or so. And because of their size you can store them easily and get them out to use in your loungeroom, on your porch, or take them to a park.
You won't get as strong, fit and mobile with kettlebells as you would with barbells, running or yoga - but it'll be more than enough for good health. Nobody needs to squat 200kg for their health. If you can do a good goblet squat with 20kg or so and keep that up into your 70s, you'll never need a walking frame.
Kettlebells are good. But let's be realistic - if you want to be strong, barbells are
much quicker.