My opinion would also line up with @DJWhitJr
I think this is a situation where, for the most part, we can really only answer for ourselves as to what level of benefit or improvement is worth what cost. I also think that being happy with what you already have makes that the case all the more. So, you're happy but there just might be some unidentified thing that would make you more happy? And you're going to attempt to define a value of that "more happy".
Your experience with the ZS10s is a whole ball of factors...how they sound to you, how they fit and feel, how well they seal, what level of isolation they provide (both inherently and based on seal), how they respond at the level you're running them at, even their appearance and how the cable feels in your hand. Another set of IEMs that have those factors come together differently for someone else doesn't mean that it's going to be the same for you.
To the degree that you're like me, I think with the Westones, which are designed for musician use, by comparison, you'd likely appreciate the lack of bulkiness and inherent isolation level (i.e., the part that's not owing to the quality of the seal). $600 worth of appreciation? Who on earth can say?
That said, if you have have the funds to experiment with various chi-fi brands and models, I can't say I see the harm because I do that myself. You might come across something that checks a lot of boxes as worthwhile improvements over the ZS10s, and you might not. For me it's really just out of curiosity that's affordable enough to satisfy. I don't really even have any intention of necessarily using them for gigging. I have customs and I have Westone UM2s that I would choose to use as backups over any of the chi-fis that I've tried because in the context of stage use, I find them preferable overall...and I don't see that changing unless I come across something else that fits completely inside of my outer ear YMMV
It's occurred to me that my conception of comfort in IEMs isn't a matter of having them "feel good" (cushiony, soft, etc.), it's a matter of how little they are felt at all. For my ears, the Westones (upper left) with Comply tips disappear from my awareness that they're there more than any of the chi-fis that I've tried.
My latest buy and try set is the KZ PR1 PRO, and for me, these are actually the first ones that I've found remarkably different in my own comparisons. If you've got the itch to try another chi-fi set, I'd say check out some of the reviews/youtube videos on these and see if what they're saying sparks your interest in them.
