I have friends and clients that won’t purchase shoes if they show “toe cleavage”. This happens often when you have long toes and bony feet. I have both (Greg likes to say that I have little fingers on my feet).
I for one don’t think it looks unattractive. When you have fussy feet, showing a little more of your toes in closed shoes is the least of your concerns. Would you let toe cleavage get between you and a great pair of shoes?
Most of my shoes reveal some degree of toe cleavage.