Understand the rationale.

Providing a slightly different take on "public" access - award inventory is public data from an AC point of view. Unlike other FF programs, AC allows anyone (or a bot / scraper) to search the inventory. They could restrict that by either rate limiting it by request IP or restricting it to a logged in aeroplan user.

I am foreseeing that AC will go that way at some point in near future (like other FF programs). As and when such situation occurs - open sourcing and allowing the user to enter their own session details / credentials allows the searches to go through and any abuse will be reflected directly on their AP account.

As there's no distant possibility for AC to allow SSO for a random app (if they were inclined in something similar - Aeroplan exec's would had been more supportive to the idea) & asking aeroplan credentials of users will be a bit extreme, it will make sense to make this awesome tool work in a self hosted (either on a vps or on each folks desktop) where they can enter their own credentials