I am Type 2 on Insulin. I 'chose' insulin because the pills... one kind I was allergic to, the other kind would make me so sick I couldn't leave the house, and the third kind I tried, I would have stomach cramps bad enough to make me pass out. One kind I managed to put up with for 6 months and they had no effect on me either.
I want to lose weight as I'm a big girl, so I do the same as the Type 2s without insulin injections - low(er) carb and exercise and I tend to split my meals up a bit more than I did before to avoid spikes too.
I can however now and then give myself a little extra insulin. It happens that I 'cheat' like that and have a bit of something sweet. My insulin rarely works fast enough for me to not have a spike, but it makes it not go all the way through the roof and brings it down again in a few hours, maybe.
I was in hospital a couple of months ago with 25-30 blood sugars and ketones, so it is still to be determined if I am a true Type 2 or maybe LADA, which is a slow-onsetting Type 1.
I think if say once a month, or at Easter and Christmas you have 1 serving of something like your friend seems to do and then take extra insulin, it may be fine. If he does it all the time, he will either get bigger, or be running too many risks.
Insulin has been good for me, but it is hassle too - it's just a different kind of hassle as when I am doing exercise, I have to test all the time, I have to have my meter and my insulin with me when I go out, I have to inject 5-6 times a day and I risk suddenly 'turning off' because my blood sugar got low and I'll be really confused and sleepy and pale for a while until I get it fixed and currently I am having trouble with my thigh injections as I keep getting bruises and somehow hitting a small blood vessel.
Also, as someone said, noone told me how to take insulin exactly - I was just told inject then and then, nothing about food, nothing about reducing before exercise, nothing about lenght of needles, nothing about sick-day rules or carb-insulin ratio. That was learned in a hurry off the web and especially this forum. Type 1s I think have more targeted education available.
Type 2s have less options in the short term, I suppose, than does a Type 1. But a Type 1 will 'never get better'. They can get better control, better at managing, but they'll always need the jab or things will go awfully wrong. As a Type 2, you can get such good control that watching what you eat and making sure you get some exercise is the only thing you might need for a long long time. So it's a different level of freedom depending on your viewpoint.
-M