I know someone who uses the gateway but it was a long while before we (I) found out that he didn't receive edits or emoji reactions, which may or may not have caused significant miscommunications.
I've always used the sed style edits over the IRC gateway. Then someone let me know that they don't work. I always thought that people just read them and parsed the correction manually rather than relying on their client to do it. It's not like I use very complext sed substitutions.