Aye, I guess first it must have been an intimidating sight to have all those riders "enhanced" by their wings coming at you (crest and plumes found in military dress all around the world basically serve that purpose (it would frighten not only the horses of the enemy). The effect is of course much more pronounced if it is a mass of people with that dress rather than an individual), then there is that whistling noise which those wings gave. Furthermore the poles of the wings worked as a kind of protection of the riders back against slashes (most of them wore armour but mostly on their front, often a cuirass which however did not offer much protection to the back), finally the wings also worked as a protection against the lassos which were sometimes used by Tatars to unhorse and / or strangle their opponents.
Your turn Myrkin.