Cost and versatility. The turret becomes obsolete if you change the load or put the scope on another gun. I also find that for long range the increments get so small that it's though to dial every distance as you usually see only 100 yard increments. I never got what was so hard or time consuming about dialin exact mils or moa for a long range shot the extra second it takes shouldn't matter as you shouldn't be rushing it. For close range snap shooting yre probably not dialing in anything. Just my opinion.
Elevation makes a very large difference in drop so a turret made for sea level would be useless at 8000' elevation. If you're talking +/- a couple thousand feet then it wouldn't be enough to matter.
I prefer to have my turret set up in MOA (or MILS) and tape a drop chart to the side of my stock. That way I can change the data for the areas I hunt.
Another option is custom turret labels. For a small fee they'll send you customized tape labels that you wrap around your turret. I haven't used them but supposedly they're high quality. That way you can just change the label for different loads or altitudes, etc.