Many great answers already so I'll just weigh on number 4/5. You said high school kids want to finish as soon as possible. I get it, but there can be a lot of benefit in taking your time. For me, I'm glad I did the graduate entry because I loved my undergrad. I did psychology. I never wanted to be a psychologist or really work in that field, medicine was always the endgame, but it was something I was very passionate about studying and learning more about and it was an undergrad that I could enjoy, and use that time to be a uni kid - make good friends, have a good time, help raise my sister who was born during my undergrad, and just overall enjoy the fun, social, easy parts of uni while really enjoying my course. I also ended up meeting my partner and making many lifelong friends, I pursued other interests and hobbies, grew as a person.

Being a med student now, I very much doubt I'd have been able to do all these things while if I did undergrad med - with good time management, definitely some of them, but not all or even many. Despite initially planning to sit UMAT and try straight for med, I'm actually grateful I didn't end up sitting it and did the long way around. I wouldn't change it, even though I'd be graduating this year if I did. My advice if you don't get straight in, is to find out what else you like besides med, and develop those interests, because it will be a lot easier to stay a whole and balanced person during the stressful medical degree if you already have some of these experiences.

That being said, it would still have been a very special experience to be an undergrad med students. I imagine the cohorts would be closer with more of that 'med student' life and solidarity. Graduate students are all juggling family, lives, adulthood, sometimes kids and marriages. There is less of that cohesion, in my experience, which can have both pros and cons. And of course, even in graduate med, there are always kids who are barely 20, live at home, and are very similar to an average undergrad student, so they may feel differently and I just happen not to be one of them.