[AmigaBlizzard]

That's also the only place where I would use them anyways.

But when I think about it, OnGameModeInit could just send all data-loading queries one after the other using tqueries instead of unthreaded queries.

Then all these data-loading callbacks (where it loops through all rows to read the data and store it in arrays) must be finished before any player logs in.

Even when a player logs in before data-loading is finished, his account-load query comes after the data-loading queries and must wait to get executed anyways, so I think it won't matter that much if a player logs in before all data has finished loading.
Tqueries after all are executed sequentially and the queries in OnGameModeInit are executed first anyways.
This will make sure the data is loaded first anyways before any player can actually log in (his query will come last in line).