ark-curve25519 is used at run time in 7 crates. It is a direct run-time dependency in 2 crates. It's used only as a dev dependency in 5 crates (of which 3 directly).

Depender (with downloads and own rev deps) ark-curve25519 version
550 7 ark-ed25519 ^0.4.0
150 2 kvac dev ^0.4.0
140 1 bulletproofs_plus_plus dev ^0.4.0
110 nimue dev ^0.4.0
4 ark-bulletproofs dev ^0.4.0