To be formal, when discussing color folks talk about 'spaces' often without realizing/remembering that the terminology is that of linear algebra. Conversion from one space to another is accomplished by multiplication by a 3x3 or 3x4 matrix. A neat insight into the process is understanding that the matrix in effect gives a different point of view of the same solid in 3D space. So it is always the same color 3D object but seen from different perspectives.

If we can shift the point of view of the captured raw data cube to that which gives us what we call an XYZ projection, and from there to sRGB's, we can just as easily shift the point of view back to XYZ's, then to Adobe RGB's, then to ProPhoto's, etc. indefinitely, without ever touching the raw data solid, which is what it is, what it was and what it will be. All captured 'colors' are present all of the time. They may be more or less squished or stretched but they are there nonetheless.

All these transformations are accomplished by floating point linear matrices that look like

this. Because they are linear, they are 100% reversible. In other words, as long as you stick with floating point math, there will be no/zero/zilch practical penalty for moving between and/or working in any of these spaces. Limitations are only introduced when working with unsigned integers at lower bit depths (say 8 bits).

So given the fact that if one sticks with floating point one can effectively use any color space one wishes without any penalty of any kind whatsoever, what color space should one use in practice in such a case? What I do as a matter of course is to work with 14+ bit data and choose a color space that closely matches the output device that I am viewing the photo with while rendering, so that I will see what I am doing. My monitor does close to 100% Adobe RGB, so that's the working space I typically use*.

But that's me, to each their own of course.

Jack

* This doesn't stop me from using larger color spaces on some images that I want printed, although my experience is that in such cases more than one trip to the printer is often necessary before a satisfactory result is obtained.