Alliance Benefit?

With an alliance you can assist other people with their calls, but they can also assist you. Useful when you have no units free. You can also share hospitals, allowing others to use them with a customizable Tax. When you start courses at your schools you can allow alliance members to join them and as with the hospitals, you can choose how much to charge them per person, per day.

I believe that it is only Co-Admins and Admins who are able to actually start the large scale missions (Major Fire, Unannounced Demonstration, Pile-Up) or an Alliance event (Storm, whatever size and frequency you want).

If you have already got schools and won't have anyone near you then I personally don't think you would really benefit from being part of an alliance. Though I believe you can start one up and just start the events for yourself. Allowing others to join is optional as they have to be denied/approved.

As Pottyscotty said alliances are great when you have a group that is playing together in a close by area but lacks a lot if you are playing alone and far from others. Also they are great for helping lower players to advance and get there first few stations going. Using the Alliance missions and sharing the larger calls with newer players allow them to respond to call that pay well to help them gain the credits to start building up so they are at a good point where they can run calls on their own and they have a few units built up.