Crunch Compression is a controversial topic, and different, informed content creators will disagree on whether you should enable or disable it.
This page will outline the various points that may be brought up around this subject.
This is a fact:
Using Crunch Compression will result in a reduced texture asset file size compared to the same texture without Crunch Compression.
This is a discussion point:
Crunch Compression reduces texture asset size. The question is, how effectively does it affect the download size?
Crunch Compression is often used to "reduce the download size". The download size is based off the size of the bundle, which is a compressed package of all of the assets.
In order to reduce the download size, we shouldn't look at the difference between the asset size before and after Crunch Compression. Instead, we should look at the difference between the compressed bundle size before and after Crunch Compression.
Metrics needs to be collected here to support the discussion point
This is a fact:
Once read and decompressed, textures with Crunch Compression live fully uncompressed in the VRAM.
Crunch Compression is not meant to reduce VRAM usage, so it makes no difference compared to a texture without Crunch Compression.
This is a fact:
Crunch Compression is a "lossy" type of compression. Lossy means that the original data is irreversibly lost.
The same texture will not look the same with and without Crunch Compression.