Popcorn Ceiling vs Smooth

Fighting and killing all of echo may defeat the naturality of the sound. And amount of echo should be present so to feel an atmosphere of a real performance hall and naturality of every instrument and voice you're hearing.
Some studios don't kill echo completely for that purpose.
Sound with no echo is lifeless IMHO.

Ceiling mostly affects the sound isolation from other rooms. If that's not your concern, you shouldn't worry. It's more depended on walls and position. If you're planning to sound-proof the room, than flat ceilings are much easier to work with.

But every standard recording studio I can recall being in was dead as can be.

Agree, but one can choose studio with partially defeated echo realizing that there won't be possibilities of successful overdub or isolated recording of each instrument. Whole band shold start from AtoZ with no interruptions or failures of either electronics or musician's fingers just like on the live concert. It works super great for small jazz band with good recording equipment.

For home entertainment I don't see neccessity of defeating echo heavily. It's much easier achieved via closed back 2
headphones.