A saddle can be compensated to make up for intonation deficiencies on a specific instrument, not to "improve the sound". I think offering a pre-compensated saddle as an accessory is dishonest on the part of the seller.
The "sound" will only improve if the new saddle is of a more effective material (or if the previous saddle was defective in some other way). The intonation will change, but the chances are one in a million that it will improve either way you install it.
That being said, the change may be so infinitesimal you won't be able to hear it. So you probably won't know if the intonation is worse or better. As for anecdotal claims of improvement: imaginary.
If you want a compensated saddle to improve your intonation, the only way to do it is have an experienced professional compensate the saddle on your instrument.