In my opinion, thermal pads are better suited for components that need just that little extra bit of heat dissipation to perform adequately, i.e components that are < 10° C from being able to be passively cooled. Voltage regulators come to mind.

So in that instance, if the thermal pads are reasonably well installed, the components should be just fine, since we're working with much looser tolerances.

When you need active cooling, the manufacturing complexity increases to the point where the convenience doesn't really make sense, since you have to get it right, so thermal paste is the way to go.