Thanks, everyone for all the replies! Nice to get reviews from those who have already experienced using these shoes in similar conditions to what I might have!
In light of the majority of the reviews, I think I will pass on these. It seems to be what I expected - they wouldn't offer enough support for me for lots of heavy daily walking. I am one who can't wear flats for even an hour or two, since they offer little or no support, so it's helpful to see that these sneakers seem to compare the most to flats. And I have enough other sneakers that don't need added insoles, so buying some for these would just be an added cost.
And I didn't expect to hear so much about an odor after wearing these, especially since their website makes a big deal about how you can wear these without socks and have no odor. Again, glad for a real world view!
Thanks again all!