Closed muzzle end tends to collect dust, lint, grit and debris over time. Open muzzle end tends to shed more easily.
Naturally, the closed end protects the muzzle more completely. It is always possible that we might sit down somewhere and bang the muzzle end of the barrel on something unintentionally.
Open muzzle end makes a slightly shorter holster, while the closed end takes a bit more length. Makes a little difference when getting into and out of the car frequently, especially with the longer-barreled handguns. We are only talking about 3/4", but it can be a factor.
I always tried to allow for drainage in closed-toe holsters, a little open space to let water escape rather than filling the holster while out in the open during a rain or snow storm.
For occasional uses I doubt most folks would notice any difference. Those of us who have carried every day for years on end might have stronger preferences.