In fact, yes, that line is part of older messaging for Maple T.A. We just haven't updated the video yet (and, frankly, forgot this phrase was in the video description). Please note that we never claimed that Maple T.A. was the only system capable of doing mathematical testing. What we said was it was the only system designed for mathematics. Maple T.A. was conceived specifically with the needs of mathematics in mind, unlike other systems which either don't have any special for mathematics support, or (like WebAssign), which added in mathematical testing to an existing system. We believe a better product results when you plan for mathematical support from the very beginning. However, as the market matured, we found that the original message was confusing people, so we have been transitioning our marketing materials to stop using it.
Maplesoft Product Manager, Maple T.A.