I have a Dyna S and coils on my KZ1000 courtesy of some previous owner and it seems to work very well. My KZ650 still runs points, although I have a relay conversion to ensure full volts at the coils, it starts and runs really well as does my 73 Triumph Tiger with points. I grew up with points so I've spent a lot of time adjusting and "fettling" them. I personally thinks points are highly underrated and electronic ignition conversions somewhat overrated. Yes generally I prefer electronic ignition, just because it's one less thing requiring adjustment and attention. particularly when you have several bikes to keep on the road, but it seems to have become conventional wisdom that you must ditch your points system immediately, and at all costs. This simply isn't true we all drove thousands of trouble free miles before electronic ignition became available. One of the benefits of being a teenager living at home was that I had time to set the gap and timing almost weekly to squeeze maximum performance from my bikes
In reality many classic bikes don't get ridden enough for point cleaning and adjustment to be necessary more than every few years, so it's not a big deal.
The downside to electronic ignitions can be the bike won't start if the battery is dead on some models, so you can't bump start them, and if they do fail they are likely beyond a road side fix - however now they are extremely reliable. If you need new points, condensers and everything then it probably makes sense to put that money towards an electronic ignition, but you should never feel it's compulsory.
One reason I still have my points on my KZ650 is I bought a whole GPz750R1 parts bike, primarily because it was very cheap and I made money selling the parts on eBay, but also because I wanted the oil cooler and oil pan and the electronic ignition to convert my ignition system - but I put the ignition parts in a safe place in my shed and have not been able to find them for 4 or 5 years, I'm sure they''l turn up one day, in the mean time I'm not buying a Dyna S for it when I have a perfectly good OEM system hiding in my shed
although I bet if I did buy one, I'd find the parts the next day
I've looked at them for my Triumph, but that starts and idles so well I've yet to feel it necessary. One thing I like about the systems available for the Triumph is they do away with the mechanical ignition advance, using their own programmed advance curve, which is a big improvement over the mechanical systems which tend to go to full advance too early. I'll probably buy one eventually for that reason alone.