Just for some context, back when the earth was cooling and all we had was analog tape and outboard gear, you sometimes needed to process signals on the way in. For example: if you only had one compressor, but knew that you wanted to compress the kick, bass and vocal, you would have to compress some of those as you record them because you could only compress one during the mix.
With tape, if you wanted something to be very bright, you would want to add that EQ on the way in, because if you add a bunch of high end in the mix, it would also bring up the tape hiss.
You also didn't want to record any useless low end (thumps and rumbles that weren't part of the sound you were trying to capture) because that would affect how the tape reacted to the signal.
Some people learned to record this way and still chose to use this method, even if it isn't strictly necessary.