Image using XZ/ZSTD instead of ZIP


I’ve noticed that images are all using the ZIP algorithm which seems… pretty inefficient, compared to others:

-rw-r--r-- 1 user user 2862059520  5 sept. 22:34 eos-r18.tar
-rw-r--r-- 1 user user  946774568  5 sept. 22:56 eos-r18.tar.pxz
-rw-r--r-- 1 user user  902393948  5 sept. 22:34 eos-r18.tar.xz
-rw-r--r-- 1 user user 1257669422  5 sept. 22:45
-rw-r--r-- 1 user user 1032798439  5 sept. 22:34 eos-r18.tar.zst

.tar is a simple TAR archive from the downloaded ZIP, uncompressed.
.tar.pxz was created with pixz -6 -k eos-r18.tar eos-r18.tar.pxz
.tar.xz with xz -9 -k eos-r18.tar with zip -9 eos-r18.tar
.tar.zst with zstd -19 -k -T0 eos-r18.tar

The difference seems worth it to me.

So… is there any technical reason for using ZIP instead of a better alternative? Memory needed for decompression? AOSP supported image format?