It's NOT going to improve the "sound quality"...
Pros use a master clock for a couple of reasons - You can synchronize multiple devices down to the exact-sample no matter how long the recording. Normally each interface has its own clock so it you record with two interfaces and they will drift apart. For example, over the length of a concert you'll get phase differences if not outright beats/notes that are out-of-sync.
Consumer soundcards can differ by enough to cause tempo problems over shorter periods, or you can even get pitch differences. This can cause big problems when musicians are collaborating, each recording on their own computer. (It's usually NOT a problem if they are using "proper" audio interfaces.)
Also if you are working with audio/video, timing can be very critical. You often want to know the "exact" playing time with movies/video and if the audio and video drift out-of-sync a fraction of a second by the end of a movie, you've got "lip sync" issues.
A typical crystal is rated for frequency accuracy of about 100ppm. (Wristwatches are "trimmed" to be better and I don't know what the typical specs are.)
This master clock is rated for 0.001ppm.