There are hashes which require much less computing power and thus have better throughput if you don't require cryptographic security (examples include FNV-1 and MurmurHash). Using SHA-1 because you "don't need it for security" is still a poor choice.

I'd also argue that the default choice of hash function should always be a secure one until a strong counterargument is given, because it turns out that at some point most developers assume hashes have some minimal security properties (Linus always claimed that the choice of hash function in Git was not about cryptographic security -- and yet the security of the GPG signing of Git objects depends entirely on SHA-1 being cryptographically secure because Git signs the commit hash, and the BitKeeper attack against Linux's source tree only failed because the attack was done so poorly they didn't try to find a collision in the commit ID hash function). Better to be safe than sorry.