Its nice that its opensource, backed by Internet Archive and the Controled Digital Lending program is cool too, but how is it possible that a project 14 years in development is such a mess? Just try and search for some popular books and see for yourself, the most important feature - search for books well, is not present. Basic features are missing, book data is often wrong, etc... honestly why would I join such a project instead of starting a new one?
And yeah, searching needs some work! That's on my task list for this month. Just this Friday I spent most of my day working on updating our search engine, Solr, from 3.6 to 8.7 (wip!). But search is a _BIG_ pain point. We're a small team with a big long list of things to do, but we are making progress! This year we updated to Python 3, switched most of our production environments to docker-based for easier deploys and to give open source contributors more control of production infra, added reading history stats for users, added a new interface for exploring books, worked on a novel recommendation system, added text selection to the online BookReader for public domain books, added GoodReads importing, grew our community, added the ability to search by classification, and much, much more (you can see highlights from our year here: https://github.com/internetarchive/openlibrary/issues/3891 ).
There is still _definitely_ a lot to do, but I think the biggest reason worth using/contributing to Open Library is likely its open source community. Anyone can jump in and help make improvements to the system (as they very often do!). Personally, I think it's more likely that a system with a community will survive/flourish than one maintained by a single person (I also wondered whether I should just create my own before contributing to and now working on Open Library!). And there are also loads of different tasks associated with a site like OL, which would be impossible for me to do if I was going it alone.
If you would be interested, checkout the GitHub repo: https://github.com/internetarchive/openlibrary . It's very active, and you can get an idea of how we work :)