The purpose of a swedish - or crank - with a flash is for use with a loose ring snaffle. The flash is meant to stabilize the bit in the horse's mouth that the loose rings are not clanging around.
that's the flash part though. Same function essentially as a drop noseband, which IMO is the better option. Maybe that's just me, but trying to combine nosebands [flash strap on any cavesson type is trying to combine a drop and a cavesson whether you like the idea or not!!] just doesn't work. You want to stabilize the bit use a drop. Just my opinion.
What is the purpose of a crank, in and of itself [mine doesn't even HAVE a flash attachment tab], if not to make it possible to tighten the **** thing about 4x as hard? Why would you want/need the pulley system if not to crank the horse's mouth shut harder than you can with a flat buckle?
I'm not buying that they're easier to buckle. I find the opposite. And my filly is a BIG girl, 2 years old and 16hh+, and can be a bit head shy. Her old bridle, since grown out of, was a plain flat cavesson, and was much easier to buckle than her crank. The leather is nicer in the crank too, so it's not leather quality.
I did catch the part where you said you prefer flat buckles, but unfortunately that isn't the case for so many, many people. I have spoken with people who won't use anything BUT a crank with a flash. Same people, generally speaking, have horrible hard and unstable hands, and are usually mounted on young horses, or horses they trained themselves.
I have NO PROBLEM with a crank that is used by someone who actually has a clue. Unfortunately, too many do not. They put bigger and bigger bits in their horses' mouths and then progress from a plain noseband to a flash [misused, to crank the horse's mouth shut] to a flash on a crank [tightened as far as the person can physically manage] and occasionally on to a grakle also severely over-tightened. Then if the horse reacts negatively, it gets branded dangerous and euthed. Or worse, ends up like my gelding a couple of owners ago - neglected and forgotten in a pasture somewhere.
The above process of bitting up and putting bigger and bigger nosebands on the face is what happened to my gelding - a superb jumper and event horse - and on top of that, a rider who REALLY didn't have a clue and was jumping wayyy higher than they were ready for, therefore was yanking on his mouth over every single fence.
And they wonder why the horse starts stopping, bucking, rearing, doing everything in his power to ditch his rider? He gets branded dirty and dangerous and 'retired' from competition and riding [he was TEN YEARS OLD when this happened and perfectly sound and sane, just the rider was an idiot], is lost to knowledge for four years, and turns up horribly neglected [a ONE on the body scoring chart with feet that clearly hadn't had any attention for a very long time] and essentially abandoned at a boarding facility.
This is just one horse's story but you see how much damage harsh tack in the wrong hands can do... my boy still has huge issues despite the fact that he is now rising 18 and for the past almost four years has had riders who actually have a clue. I had a run-out while jump training a week and a half ago and he just freaked out. Bolted, took me ten minutes to get him under control again. Poor guy :( [he ran out because I keep him forward enough that he really can't hit the skids, and he has a knee issue I didn't know about... I'm guessing the big stuff hurts him because he has done bigger in the past and is an incredibly honest jumper]
I personally, honestly, believe that people should have to have a license to use anything more than a plain noseband [MAYBE a flash] and a snaffle bit. All tack has its very valid uses in the right hands, with a few notable exceptions that have no place in a horse's mouth, or anywhere near one in any form, but unfortunately all too often it ends up in the wrong hands.
Apologies for the rant, it's a topic that hits a few very sensitive nerves for me because of what happened to my gelding.