That may be the case for casual listeners, but there still exist people who really love hearing a beautiful lead with all the bark and sizzle the original hardware gave it - you might not notice it's gone if it's translated to software, but if it's there it can absolutely vitalize the recording. A big part of that, to me, is not whether digital is accurate enough or whatever to the sound, but the dynamics behaviour, the playability of it. It takes an immense amount of extremely high level DSP mathematics and careful implementation to get a truly convincing analogue filter reproduction, and so those are both rare and computationally expensive. On the flip side of the argument, I'm not aware of any digital-only filters with their own, unique, nuances that grab the ear so compellingly yet, although there are certainly tons of implementations of standard filter styles and even (Modor comes to mind) some uniquely digital varieties out there. The problem is the math - analogue circuits behave in some highly complex ways, if subtle, and getting those complexities both identified (hard part 1) and modelled correctly (hard part 2) in a *dynamic and interactive manner with the rest of the system* (very hard part 3) is both a technical and mathematical challenge that is still not fully perfected. We can create ideal static filters, beautifully close and accurate "enough" emulations of analogue, and the mathematics hold the promise that it's possible to equal any analogue behaviour we wish - this much is clear. But the real world experience of such things often (though, not always) deviates from this on many counts.
So, I don't see it as an analogue-vs-digital thing at all, there are digital filters that sound far better than some analogue filters to my ears (of course, I am not saying there is a digital *Moog* or *Curtis* filter that sounds better than an analogue *Moog* or *Curtis* filter per se, just that *some* digital filters sound better than *other* analogue filters), and there are digital filters that can do things no analogue can at all (linear phase, for instance).
That said, as to whether it matters if a user can hear it "in a mix" or not - well, great music can be made on a toy guitar or a cheap accordion or, hell, a rubber chicken. But in many cases it's considered 'better' when performed on a more refined instrument. And that's a big part of why it matters at all.