GROLSCH & FISCHER ALSACE!
Face it, the aforementioned beers both taste better than either Schaller or Dunlop. I've found a new organic micro-brew that has purpley-bluey-blackish strap locks if you don't like the flashy red/orange of Grolsch or Fischer Alsace.
A: They work, well.
B: You can't install them incorrectly.
C: Easy-Peasy strap removal for instrument stowage in case.
D: Regular replacement is recommended and enjoyable.
... Rubber washers shrink and fail - metal is pretty stable.
No problem. See point "D" above. I inspect my strap locks every time I use them, if they show signs of deterioration then it's time to pop open another tasty Grolsch.
I've also used the [Invalid or Expired Link Removed], made of little plastic discs where one rotates within the other, there's an oblong hole in one disc and the other disc rotates to a "locked" position. Well, the beer washers win again, as I've had the little plastic disc rotate and come off.
No strap lock will prevent a screw pulling out of old wood, like it did on my SG, or prevent a strap button that breaks.
The beer washers aren't up to the task of spin tricks, but I don't ever throw my gear over my shoulder unless it's in its gigbag.
I'd use the beer washers even on an exotic bass. I'm not cheaping out on anything, why spend extra cash on something that doesn't necessarily work as well as the washer from a soothing libation? As for PITA straplocks, that's installing any of the popular aftermarket straplock systems. My strap goes on and off with the greatest of ease in a split second with my flexible little beer washers. Installation time? Laughable.
...It's your bass so you are of course free to treat it as you will, but the washer/cap thing (at least to me), is like the guy who spends 2~3K on an r/c race car then complains about a $10.00 race entry fee...
What's with the R/C analogy? Total non sequitur. Okay, so I drop a stack of cash on a Ka$ching bass like some R/C enthusiast shells out for an exotic race car then what is the equivalent part of complaining about the entry fee? I'm not complaining about anything, I'm rejoicing my bass purchase with a new set of straplocks, whose exotic packaging also happens to contain a delicious malt beverage.
Maybe a better analogy for your point would have been: buying a Ferrari and then gassing it up with the lowest grade petrol. My retort would be why buy a Ferrari and then feel the need to spend an excessive extra amount of cash for a new set of wheels for it when the original wheels are just fine. Buy some locking wheel nuts for it for added security, maybe. Then you can afford the Swarovsky Crystal-embedded Ferrari-by-Gucci key-fob. Of course, if I had the cash for a Ferrari, I'd spend it on a vintage VW...
Use whatever you like, whatever works best for you regardless of budget, the beer washers fit my needs best.