The trouble with that example is that it could more simply be written:
openssl base64 <somebinaryfile
On the plus side, you do get a prize for suggesting it [1]
Something involving bulk binary data moving over a pipe which isn't an indirect redirection would be:
gzip somefile | ssh user@host "gunzip >somefile"
Although, again, there's a perfectly good -c flag to SSH that would do the same thing.
Probably the most common example of tool-to-tool binary communication over pipes is:
find -print0 | xargs -0
> On the plus side, you do get a prize for suggesting it
Good catch! I actually use another command that generates binary output that I pipe to OpenSSL to convert to base64 but rather than type out the full command I thought 'what's the easiest way to get some binary data on stdout' and 'cat binaryfile' was it.
Pipes work fine with binary data, you just need to be piping to a tool that works with binary data rather than text e.g.
cat <somebinaryfile> | openssl base64