[mD5pPxMcS6fVWKE]

No. MD5 is a cryptographic hash function. For the purposes stated one uses a non-cryptographic hash function, such as seahash. The difference is the latter is much faster but does not provide protection against an intentional collision.

[a1369209993]

1: MD5 still provides preimage resistance (both first and second), which is sometimes useful.

2, and my real objection:

  $ md5sum /dev/null
  d41d8cd98f00b204e9800998ecf8427e  /dev/null
  $ seahashsum /dev/null
  <stdin>:2:0: seahashsum: command not found

That said, my main point was don't use SHA-1, because if you actually need a half-broken hash function for something, MD5 has all the same properties (good and bad) for cheaper.