Yes indeed, building ducting and then plastering over it seems like an effort to me.
My perspective if I'm burying pipework then it has to be joint free, like wet under floor heating.
I used to put pipes in walls on new builds and that was plastic but there was always a drama when the kitchen fitters went in. Then there would be joints in walls ripe for failure in about 10 years.
There was no time to build ducts, just metallic tape so they are picked up with a stud finder.
I suppose if you have the money and the time you could build purpose made ducts that can be accessed, much like the ones you find in modern flats.