There are so many things you can do with a 45 degree fitting.
The first and most useful is to connect two 45's together with a straight connector (#13093) and make your own sweeping 90 degree corner. This puts an end to the air flow loss experienced with most 90 degree fittings.
Next you can use the same connector to make a 5" offset when you need to get around an obstruction as you run your lines along the wall of your shop.
... and won't they be handy connected at your machines to allow the hose to drop off more freely rather than bend so abruptly.