As a power user, who uses spreadsheets every day professionally, OnlyOffice isn't full-featured enough for my needs. LibreOffice is the only free software that's adequate for my job.
Apache OpenOffice hasn't had a major release since 2014 whereas LibreOffice, its de facto successor, is actively developed and modern.
Unfortunately OpenOffice still has name recognition which leads casual users to still download it as a replacement to commercial office suites, despite being very out of date. It's kind of become a bit of an embarrassment to open source software and really should be discontinued, but a small handful of developers insist on keeping it on life support.