It's nothing special, you're not missing much. Japanese airlines don't invest much into the lounge experience. Both JL and NH F lounges are just marginally better than the same C lounges. It's nowhere near what you'll get from the CX F lounges, let alone QR Al Safwa.

It's funny, I often cite OW's F lounges as the key differentiator between OW and *A, but then only a few OW airlines actually have a decent F / Emerald lounge anymore. JL isn't one of them. It's a status lounge, not an F lounge.