Vintage Phil Wood hubs were the product of limited resources. A small operation with minimal tooling can make sealed bearing (cartridge) hubs with ease. Cup and cone require way more resources and capabilities, bearing inserts, grinding centers to heat-treating etc.
By utilizing readily available (and inexpensive) cartridge bearings, you can produce a hub that will do the job. Especially in the era of the freewheel. Chris King had to invest a lot of money to produce the cassette hubs we see today, and now Phil Wood offers a cassette hub.
Where the Wood hubs "shone" was in that some inherent cup/cone issues were eliminated by the sheer simplicity and diameter of the inner "axle". Due to the very nature of a cartridge bearing (design/construction) they will always have some "play" but not enough to matter for the most part. They are very robust, but will never be as slick as a super high-end cup/cone. They got a reputation for being "silky smooth" but that mostly stems from resistance from the seals giving the impression of absolute precision. Pop the seals on a PW hub, and run light grease/oil and you will detect some radial/axial play quite easily even with QR installed properly. It's just in the nature of the design.
I run Phils on my single speed, but mainly just to have some variety in my collection.