Quite few people have added the NP5 to Gen1 Naim streamers. All have reported an uplift in sound quality.
@Ron posted recently.
Low price doesn’t necessarily mean low quality.
The NP5 appears to use the same coax socket that Naim use in the ND555. 
I doubt many dealers would be promoting the NP5, (or any other low cost high quality streaming bridge).
Instead of customers spending a few hundred pounds upgrading Gen1 streamers, they’d prefer them to spend thousands on a new streamer.