Keeps me grounded.... and trains my toes to not overlap.... an issue that happened when I used to wear Easy Spirit shoes a lot.  The soft bed ruined my feet.
These "flip flops" provide perfect support and prevent my ankles from rolling in..... I see this as a potential problem for people I see wearing regular flat flip flops.
They are true to size.  Takes a little getting use to, but I'm a believer in these now!