The "convenience outlet" is an increasingly rarer beast.
Keep in mind that some power bricks use a barrel jack for an external wallwart to power the brick. Using a 3-prong AC socket and cable requires room inside for the AC->DC conversion and step-down, making the brick necessarily larger and less pedal-board friendly.
That's not an argument for leaving such outlets out. Just an explanation for why you don't see them that often.
One other brick-type PSU brand that I can recall offering a courtesy AC outlet is Cioks. Some of their Professional Link series models (e.g. DC-8 Link, DC-10 Link and Overkill) have it.
None of my brick-type PSU (a Cioks AC-10 and a Truetone CS-12) came with a courtesy AC outlet. It could come in handy to plug a pedal that was built with a hard-wired AC cord, such as some of the vintage EHX pedals.
Come to think of it, one of my amps has an AC outlet on the back. I have this amp for more than 20 years and I don't recall ever using that outlet. I suppose I prefer wall AC outlets to courtesy AC outlets.
Convenience outlets on amps used to be a regular common thing. Less so these days. I wonder what manufacturers conceived of those outlets being used for. Sometimes, it was just to plug in another guitar amplifier because there weren't enough wall outlets.
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