Is there any point for (new) .bz2 archives in the era of Zstd?
It takes years for bzip2 be in every Linux Distro, and we _still_ doing gzip.
LZMA / xz tool are start to get more support, but they are nowhere near universal.
No idea when how long zstd will need.
For Windows systems, 7-zip (.7z, similar compression to .xz) is a free download for Windows 10, and Windows 11 can open up a .7z file with a simple double click.
.zip and .gz no longer need to be used here in 2026.
"It deletes empty folders" and "Let me know if this is a problem for you"
NEVER DO THAT. I know you meant well, but the first rule of any program is to NEVER automatically delete something without informing the user. NEVER. Users keep empty folders for structure, reminders, or placeholders because software will dump files into it later when it's run. If it was there when they zipped it up, it should be there when they unzip it. Otherwise they'll check the before and after and it will show some folders missing, create confusion, and the user will run off trying to find out if anything else is missing.
Example: A user zips up a program. Some programs are coded to look for a folder and dump files into it, if the folder is missing the program will fail. I've had that occasionally over the years. Not all programs will recreate a missing folder.