Now this isn't me complaining but this is just me asking a normal genuine question about their presence on Mina Rau instead of the Imperial Army for the planet.
Granted this is more of a debate since well The Stormtroopers making presence on backwater worlds like Tatooine in the Original Trilogy and even in Rogue One despite being well the elite army in case if everything goes wrong. But at least with those cases. The Stormtroopers were looking for the droids on Tatooine while one could argue that Saw Gerrera's presence on the planet result in the Empire sending in the stormtroopers instead of the Imperial Army.
Now they did sort of did kill two birds with one stone where they had both Stormtroopers and the Imperial Army on Ferrix for the Ferrix Riot. But still would make a lot more sense at least lore wise in sending or at least have the Imperial Army for the Imperial Supply Census on Mina-Rau considering the Stormtroopers are well the Empire's elite in case things get really serious.
Like I said this isn't me complaining just a curious question that I had after watching the first arc of Andor Season 2.