I don't even know what it is so I wish I had looked it up first but now it's too late. Also mysql will aide in later replicating the application between different locations to ensure availability for each office.
Yeah the WAL basically makes "concurrent processes reading/writing to the same database" work magically, where as without you'll get all sorts of issues and timeouts. I don't know why it isn't enabled by default, or at least more prominently advertised as an option.
Initially, WAL mode was off by default because older versions of SQLite do not support it, and it is a property of the database file. Thus, a database created in WAL mode would be unreadable by older SQLites. But WAL has been available for 6 years now, so it might be reasonable to make it the default. We will take your suggestion under consideration. Thanks.