Big Blue Test was just a way to get more people to test their blood sugar. I know there are a few people with diabetes out there who are in denial and don't test their blood sugar, it might help them snap out of it and get more pro-active... but, when I realized that it was an "effects of exercise" experiment I became much more interested. I do this everyday and since I use a CGM I am seeing the impact immediately. It's no small thing. I'd encourage you to do it if you haven't.
When I take a brisk 20 minute walk I will usually see my insulin sensitivity kick in and my blood sugar will normally drop 30-40 points. It can make a correction work about 3x faster. For me, it's great to take a walk in the morning, and I don't have to bolus for my protein breakfast. I also take our dog for a walk after dinner and keep my post-dinner numbers in check.