The issue with compression is the requirement for decompression. - Decompression takes time, memory, bandwidth and CPU cycles.
Sometimes compression can be justified, like in the case of Virtual Texturing if you have the DRAM to play with.
The Carts themselves however due to their large amounts of bandwidth and low-latency relative to optical media tend to be able to stream data on-demand much more effectively, even compared to mechanical hard drives they hold some advantages, so you can typically reduce the amount of Ram you need that way.
In saying that, Compression isn't a be-all end-all solution to resolving the Switch's limitations, it's a tool, sure, but not one that is applicable for every instance.
I acknowledged in my second post in this thread that not every game will be able to accomplish a ratio as big as 4:1 with compression, so I am aware of that. But at the same time it's clear that many games, including Hellblade, don't need to reach a 4:1 ratio to fit on a card that is smaller than 32 GB.
I wasn't arguing compression ratios. Just that compression itself cannot be used in every scenario.