Deciding Whether You Need OwO Lib in Your Modpack
OwO Lib is a dependency, so the question is never "do I want this library" but "does anything I want require it".
Let the dependents decide
Check the mod list of the pack you are building or downloading. Any mod whose page or metadata lists OwO Lib as a required dependency needs it present. If no mod in your pack references it, you can leave it out — it will not add content on its own, so there is nothing to gain by keeping it standalone.
Keep it when it is required
If even one mod depends on OwO Lib, keep it. Removing a required library to "trim" a pack is a common mistake that produces startup crashes and confusing error screens. The library is lightweight by design; its purpose is to avoid duplicated code across mods, so it costs far less than the alternatives.
Watch for optional integrations
Some mods list OwO Lib as optional, meaning they gain extra behavior when it is present but still run without it. In that case the choice is yours: include it for the fuller feature set, or omit it and accept reduced functionality. When in doubt, include it — an unused library does nothing harmful, while a missing required one breaks the pack.