To me, there is just an undefinable quality lacking in the Ecrou that is present in the Juste Un Clou and Love Bracelet. I think largely, it is related to the fact that the Juste and Love were created by Aldo Cipullo, in the cultural hub of NYC, during one of the most important creative cultural epochs of the 20th century.
The Love and the Juste perfectly fit into the cannon of the 60s-70's Pop Art movement, where the ordinary and low-culture - a nail, screws (or for Warhol a soup can or a Brillo box) becomes high culture (a piece of fine jewelry made by a most important jewelry house, or a museum worthy art piece)
I also appreciate the Love and Juste's sophisticated cultural references - the Love famously refers to the legendary chastity belt - which husbands locked onto wives when they went away as a (rather disturbing) symbol of commitment. Similarly, the love bracelet is intended to be locked onto your wrist by your partner to also symbolize commitment; The Juste's form refers to the Ouroboros - the overlap of the head of the screw and its tail end echo the form of the self-eating serpent.