Hi, type 1 vegetarian here... can't therefore comment on vegan lifestyle but some assumptions seem to have been made in the thread which I query.
A lot of health benefit can be gained from moving away from processed food (or not having it too often). Similarly, the cut of meat you choose and I would guess the quality of the meat has an impact on health too. I find it funny when there are vegan or veggie alternatives which essentially are ready meals. I wouldn't consider these, and would carefully look at the ingredients list. The fact that it is vegan wouldn't necessarily be an issue though, it is the processing/preservatives/fillers to add bulk which I would attribute to glucose spikes. Indeed, cheap sausages usually have carby fillers, if I ate meat I'd avoid these just like I avoid veggie sausage alternatives.
Vegetarian foods certainly don't have to be high carb. I frequently eat under 50g carbs a day, only over 100g a day at Christmas usually. I'm not trying to eat low carb, it has always just been my usual diet even pre-diagnosis. I do appreciate many type 2s would struggle on 50g carbs a day but don't understand the assumption that all vegan meals must be high carb. I also find it funny when veggie or vegan foods try to copy meaty foods. I find it is when they're trying to replicate meat dishes that the extra carbs get added. You might find cooking veggie/vegan foods yourself results in lower carb meals as you've chosen what to add.
The benefits one person perceives will depend on their goal. Don't forget non diabetics have glucose spikes. Obviously we need to avoid staying high or having yo-yos. You will approach this very differently depending on your diabetes type and other health conditions and other medication too of course.