For me, I would pass. I've been down that path and no longer own any midtier brand piece e.g. Roberto Coin, Kwiat, Hearts On Fire, Pomellato (well, I still have my Hearts on Fire diamond studs, but they are studs, so does that count?).
That said, I would only get it if you really love a specific style (e.g. the Kwiat star). I would not get it if you are trying to save money and trying to get a similar luxury brand book. I would just save up for the luxury brand piece. For example, if you really really really love a Roberto Coin style, get it. Otherwise, get a VCA (some of his pieces are definitely VCA inspired anyway).
And yes...I agree with you... these brands are hot today, but maybe not tomorrow. Not really gone, but no longer the fashionable midtier brand people flock after.
But, if you really really really love a certain piece, go for it.
Jewelry is all about pleasure. Forget resale value, forget what's popular, forget what others like.
The only important thing about jewelry is that whatever you buy, it should put an ear-to-ear smile on your face. That is the true value of jewelry for me... pure enjoyment.
I love my Kwiat star.

Agree with most of these points. If I could go back in time, I’d take an additional few months deciding to buy those mid-tier pieces, especially the ones with lower carat weights. As I age, I want more substantial pieces. Lifestyle has also had an impact on what I’ve let go. And the resale value is not there at all to help fund VCA.
But it’s OK to have pieces I don’t wear as often that are unique and more affordable. I also really like supporting independent jewelry designers. I have a fun “boutique” to play with and never struggle with finding something to wear.