I use hearing aids, but haven't tried the sound amplifiers. I do doubt they are really as good. A good hearing aid, properly adjusted, does a lot more than just amplify sound. Mainly, they help control the amplification of unwanted noise. If someone has very much loss, that noise can be maddingly distracting.
Again, I haven't tried the simple amplifiers. If you do, come back and let us know.
Yeah, it's a shame Medicare doesn't cover this. The VA will IF your hearing loss is so great as to prevent you from meaningfully participating in medical treatment. Otherwise, it has to be service connected loss.