So I just want to give my 2 cents…. I agree with everyone here 100%! Not even a question… With my bengal he only goes out on a leash which he loves! The thing is these aren't your normal cats like your cat who was in in/out cat that lived to be 18. Once my Bagheera (who is an F9, so not that "wild" keep in mind) was outside on his harness in the front yard at my lake house (flat land with water on one side) but once he accidentally got out of his harness and immediately took off down the yards!

He didn't even think or pause for a second. It was FREEDOM! Thankfully my dog was with us and she loves her little buddy and thought he was playing and chased after him and pinned him down nibbling and licking him until we got to them… After that, his harness is on just a bit tighter than normal lol scared me to death.
Now looking at it your way, yes some cats can do well inside/outside… (not savannahs or bengals!) but it's still unnecessarily risking their lives like everyone else said above. I understand you though since it seems you only had inside/outside cats. Growing up my family only had cats (2 of them) they were strays that we found around the house. Both were amazing but they were
born outside and we found them when they were at least 6 weeks old. They knew how to hunt, they knew the outside.
Your Savannah doesn't. I never agreed with having them inside/outside but who was I to tell my parents that, I was like 10 lol especially since they weren't huge animal people. We loved them but we had many scares and tragedies with them… One time one came home scraped up with cuts and the tip of his ear was gone

(obvious cat fight or possibly with a raccoon) and come to find out he contracted FIV at one point in his life..yes, feline aids. he died an unfortunate and painful death at 9 years old sneezing A LOT of blood from his nose until you could tell the point where he was suffering, we couldn't stand to see him like that and we ended his pain.

Our other cat lived to be 19… She was inside/outside for much of her life and did very well, but again had many scares with cars and other cats and we lived in the woods also in the back of a residential area, but I didn't think it was worth the risk personally.
So you see I get that you think your average domestic might do well but even if you live "in a country type area, large neighborhood, lots of woods" you still have cars around and you still have other cats with diseases like FIV and you WILL have coyotes… They are becoming a big problem in much of the country. Many are being seen in cities like here in Indianapolis in the very populated areas! Also I assisted at the Purdue University Small Animal Hospital in the Emergency and ICU, we saw
MANY cats that were attacked or hit by cars. Just because yours didn't doesn't mean your next one won't. You are risking a lot for something your cat can do without. If you feel bad about it living a life inside 100% of the time, get an enclosure or take it for a walk. Don't let it run free, it's not going to be "street smart", and it is not going to live long or you just will never see it again because it won't come back…
Sorry that was so long but I have a lot of thoughts about this… And I have seen to much to ignore it. And I don't want this to come off as harsh… just informative and a few of my experiences.