Satellites are too predictable, plus too infrequent. If there are two spy satellites that cover Iran, for example, Iran can easily know when and what direction, then presumably take some effort to cover whatever they want to hide.
A reconnaissance plane can show up without warning, any time, loiter for at least minutes, take pictures from different angles, in addition to sharper imaging. We can speculate they may also have sharper non-optical imaging, such as thermal or radar