I see no problem with that so long as it's fit for the purpose. You can bring 2 spares and have a controller and two spares for $90. Or you can bring a fresh on

I see no problem with that so long as it's fit for the purpose. You can bring 2 spares and have a controller and two spares for $90. Or you can bring a fresh one on each trip to spend $30 per trip to have zero concerns for any corrosion or similar that could happen in these environments. Once you start doing the opposite: special-puprose building a fixed controller, you have to deal with all the issues that arise. It needs to handle corrosion, you need redundancy etc. It's going to cost thousands. The question asked should be "why should we not use the cheap off the shelf solution" and only choose something else when there is a good reason.