no its not wrong. But just keep in mind that it's the musical scenario that dictates whether you use sharp or flat. Example: if you're using the Emajor scale, you wouldn't say Eb, you would say D#. This is to avoid having two notes of the same letter name in the scale. Also, musical notation plays a roll here. If you were writing an Emaj7 chord on the staff, you wouldn't use Eb, because then you would have two dots drawn on the same line - E and Eb. Make sense?
If indeed it is the musical scenario that dictates whether you use sharp or flat, why did you go with B flat and E Flat instead of the A# and D# in this particular video to demonstrate?
Thanks (big fan!)