Unfortunately insulin is not just needed at mealtimes. A non-diabetic pancreas infuses insulin into the system in tiny doses throughout the day to metabolize sugar that builds up in the blood from stress, metabolic functions, and hormonal activity. So even if you were to eat zero carbs during the day or not eat at all, you still need a little trickle of insulin 24/7, and a pretty good trickle if you are under stress. Exercise can reduce the need for insulin, but you would need to do extreme exercise constantly to avoid some insulin supplementation. If you are taking shots, this trickle is simulated by injecting a long-acting (time release) insulin like Lantus/Toujeo, etc. For pumpers, the pump delivers a little drop of fast-acting insulin every few minutes throughout the day and night.
A healthy blood glucose range is 70-100 fasting, 100-130 post-meal. Blood sugar readings for extended periods above those levels will gradually harm the capillaries in your body, which in turn impact your circulatory system, nervous system, eyes, and major organs. So keeping our BG in a normal range as possible as often as possible reduces/delays that damage, and in turn the complications that can arise from that damage. Are you needle-phobic? I always was, and having a pump helped me with that. If you are super athletic and struggle with BG stability, you may want to read “The Diabetic Athlete’s Handbook” which is full of good information.