Is it really saving bandwidth, though? The reported savings are
generally very small for me. Downloading the metadata costs something
as well.
In F33, mostly so. I generally keep up to date (update once a week),
but available deltarpms have been lesser compared to earlier versions.
I used deltarpm from the day it was introduced in Fedora, and found it
quite useful due to limited internet connection (speed/bandwidth/data
limit) — for instance TeXLive package updates (which, afait, doesn’t
generate deltarpms in f33) etc.