The half dome design is terrible because it’s always made out of shitty plastic that hardens and becomes nearly impossible to unplug. I haven’t seen the specific design seen here but there’s at least 3-4 common “snagless” designs that aren’t shitty like the half-dome design you mentioned.

Edit:

Option 1. Pretty good. Probably has the problem shown for this switch.

Option 2. Probably doesn’t have this problem, still good.

Option 3. This is fine because even if the plastic hardens the boot slides down the cable and out of the way. Not perfect, the boot can slide down sometimes when you don’t want it to.

Option 4. Fuck these pieces of shit.

Option 5. No problem on the switch but less effective for preventing snags. “Good enough”

Option 6. The best. Lots of subvariants here with different curvature of the boot and flexibility of the plastic but they all work fine. Edit++: very similar to option 2 but there some difference in the designs that I can’t quite put my finger on.

It's just luck of the draw, some premade cables have a little rubber nubbin over the tab like that.

It's there to stop people from breaking the locking tab. Lots of plug covers have those.

Add others stated, these are everywhere. I hate them.

The cable boot design shown here is better than the half-dome kind.