Hi. In general only those on certain medications e.g. Gliclazide and insulin need to take sugar readings to be aware of going 'hypo' i.e. having very low blood sugar. Many other T2s should measure their blood sugar to have an idea of what foods are affecting their blood sugar, bit it's not so essential; only desirable.
It can be very informative. I knew that I needed to avoid sweets, biscuits and chocolate bars but I was surprised to find that white bread caused my sugar levels to rise, rapidly as it happened. Same with white rice. Brown rice on the other hand or wholegrain bread is OK. Self monitoring helps you alter your diet so you can still eat morethan rabbit food, but keep your BG lower.
The second benefit is that you start to see the improvements. You improve by eatng different foods, losing weight and taking exercise. Improving BG levels all confirm that you are doing the right things and encourage you to persist. If you ever give in to temptation and eat a bag of jam filled iced doughnuts and then take a BG reading, you will wish you hadn't. You already know you shouldn't have but the high reading simply tells you, 'I told you not to'.