All so far and so good, but there are issues. The first is that all this requires energy, and as quartz watches in general are powered by dry cells that don’t push a ton of volts, you have to use power sparingly for things like driving the hands and switching the date. More fundamentally, quartz crystals, like any other oscillator in a timekeeper, are not perfectly stable – the purity of the crystal, its age, and most critically, the temperature, can affect rate; with respect to temperature, it’s the same problem that we see with balance springs in a mechanical watch.
Now, we tend to think of quartz movements as all, more or less, alike, but just as there are degrees of quality in mechanical movements, so there are in quartz. Most quartz movements drift by about fifteen seconds or so per month – this was when they were first sold (by Seiko, in 1969) and still is, a remarkable improvement over the general performance of mechanical wristwatch movements, but it is actually possible to substantially improve on that figure. An average, inexpensive quartz watch will only run to within 15 seconds every 30 days if it’s kept at a fairly stable temperature, but a very few quartz watches actually have temperature compensated movements and can produce dramatically better performance.