CyanogenMod/android_device_lge_p500 — comment on commit 197ccefc7c617264216e645a09465429f6c2717e
File:  line 0
By rmcc:

It does, but it's at the expense of gfx quality (banding artifacts on gradients).
I'd rather have 24bit by default, and users who are willing to do the tradeoff can downgrade to 16bit using the CM Settings option...