If your sore throat is caused by a thin layer of irritating mucous either coffing it up or possibly rinsing with salt water may give immediate and lasting releief. If the sore throat is from an infection it might just give some temporary relief.
I’ve never gargled salt water - but there’ve been a few times where I felt a sore throat attempting to show up - tonsils getting painful or whatever - and start using the neti pot.
Could be coincidence, but several times, that seems to have stopped things in their track.
Regardless: the warmth will be soothing (warmth on anything inflamed feels nice, even if cold does more the the inflammation), the water / rinse action will help get rid of the crud, and I believe the salt has a bit of an antiseptic effect.
In short, it’s worth a try.