In vocal training, "low belly" breathing is frequently presented as the gold standard for deep breathing. Many students are taught to hyper-focus on this area in hopes of achieving perfect breath control or resonant placement. However, it is important to understand what is actually happening in the body to avoid making breathing a source of anxiety rather than a source of support.
While you may feel expansion around the waistline or even the pelvic region, it is important to remember that you aren't actually breathing into your "guts." What you are feeling is simply the displacement of internal organs as the lungs expand and the diaphragm moves downward. While you should certainly note this happening, it should not be the singular focus of your training, nor should it be viewed as a "magic cure" for all vocal difficulties.
Attempting to breathe "in the pelvis"—which is physiologically impossible—will not fix a voice that suffers from badly adjusted muscle systems within the larynx. You can have all the breath support in the world, but if the "closer" and "stretcher" muscles of the throat aren't playing nice, the tone will still struggle. Breathing is a vital piece of the puzzle, but it must be addressed as part of the overall solution of muscular coordination.
The goal is a breath that is deep without being forced down, and lifted without causing the shoulders to raise. By focusing on healthy laryngeal function alongside your breathing, you allow the breath to respond naturally to the needs of the music. When the muscles of the throat are educated and ready, the breath settles into its proper place effortlessly.
Don't let the quest for the perfect "low breath" distract you from the actual sound production at the source. Note the expansion at the waist, trust the displacement, and then turn your attention back to the coordination of your instrument. A balanced voice is an integrated voice.