Answer:
Due to the high pressure arteries hold and it is difficult to control.
Step-by-step explanation:
Consider most of the arteries (minus the pulmonary arteries) have a thicker layer (lumen) that basically resists the ejection of blood from the heart. Arteries hold oxygenated blood to the vital organs (the heart itself throught he coronary arteries, the brain that needs EXCLUSIVE oxygenated blood, and lungs). Contrasted to a bleeding vein, bleeding from an artery tends to go faster, which increases the risk of hemorrhage and death.
if you need an analogy, think of it with a hose: if you take the hose and sever it after it's pumped into the hose on ground level, but the pump is still pumping the water, it will no longer be evenly distributed and spill everywhere.