While the spray can be useful for the greens, most sprays do not have D3 in them, so they are often lacking in that key component for indoor housed beardies. If I remember correctly, calcium/D3 tends to clump up when mixed with other vitamins, which is why the higher end or 'old school' supplements are separate - think Rep Cal , or the repashy calciums and the multivitamin lines that are separate.
If your beardie is housed outdoors, consider using the calcium spray - but honestly, most powders are still the best as far as balanced supplements for what your beardies need.
-Jen