Seems redundant, and that it might even add noise, but I thought I'd get some additional opinions.

Tons of threads on this... just search "do i need a field mixer"

if its a high quality mixer like the SD mixpre, then you gain a nicer preamp, amazing limiters, a mic on the mixer so you can make audio notes without being at the mic.

There are other features but the biggest ones are 1. far better limiters that can save your butt if the talent randomly starts shouting something interesting 2. the ability to hang the mixer off somebody else's neck and let them focus on sound while you concentrate on picture.

If its a crappy mixer? Don't bother.

Seems redundant, and that it might even add noise, but I thought I'd get some additional opinions.In addition to the other comments, a mixer allows you to feed the camera's inputs line-level signals, in many cases providing a cleaner signal than plugging the mics directdly into the camera.

And even if it's a mediocre mixer (not that I'm recommending that) you'll have much better control and likely have better monitoring and meters than just going straight into the camera.
To know for sure, we'd need to know what mics, which mixer and which camera, as well as how you intend to use them most of the time.

I am the last person on this forum that should give audio advice, but I have been down this road.
I had a SD 302 mixer for my XH-A1's, then when I got the EX1r, I felt the camera could do a good enough job for what I did, and it probably can BUT I can not.

I got much better sound using the mixer, not sure how much is actually the mixer as I am still learning but the control I have and the limiters make the audio much better. It is much easier for me to keep the levels where they need to be when watching the bouncing LED's
I had sold my 302 mixer and my new one will be here tomorrow with some new mics, and a second portable recording device.

I am determined to learn audio, and the field mixer will be part of my workflow.