How big is your JS that minification has measurable performance impact? In my experience, minification doesn't add much (if anything) on top of gzip + cache for most applications.
Yeah, the way compression works, I wouldn't expect minification to reduce the transfer sizes to any significant degree, as it's basically layering a good compression algorithm on top of a bad one. In general compression algorithm matroshka dolls tend to be inferior in terms of size and speed when compared to just using one good algorithm.
All of the comments on this post that include numbers show that using both is better than just one or the other, mostly when the code’s sufficiently large.
I agree with the recommendation of one good compression algorithm vs combining multiple in general, but is it possible that you hadn’t considered that this is a case where we have a very good lossless compression (gzip) that can get benefits when combined with a lossy compression (minification)? As wonderful as Huffman codings can be, it’s hard to compete with outright throwing “unnecessary” (to many users, maybe not OP and some of us) data away.
Does still sort of does come off as majoring in the minors.
As illustrated by the examples in this thread, the actual benefit of this isn't particularly large, and it comes at the expense of worse developer experience. At the point where this would actually have a real measurable performance impact, your application is so hideously bloated there is without a shred of doubt other things you can do to improve the performance of your application that is more impactful than minification.