Avios.com was originally a poorly designed front end for Aer Lingus and Vueling's Avios implementations, but they have now got different Avios screens within their own websites. I guess the idea was that new clients like Loganair would go this route, but now I would expect Loganair to be a bit like Vueling in terms of accessing Avios, and perhaps Avios.com being just for transfers, which is probably the best use of Avios.com for a BAEC member. For the App, the Avios app, previously the Executive Club app, may be easier for some to use and research options. given the BA app is a bit clunky in this area.