The Polish cavalry did save Europe from being overrun by the Red Army in the Battle of Warsaw (circa 1920) when Lenin was trying to spread the Revolution to the west.
That bought Europe another two decades of freedom.
The bolsheviks thought cavalry was bourgeois until the Cossacks, supporting the Armed Forces of Southern Russia during the 1919 offensive demonstrated their effectiveness. By late 1919 the Red Army had a large unit called the Konamiya or red cavalry. In 1920 they attacked toward Lvov in the south while Tcheshevsky attacked Warsaw. Stain, Vorosilov, and Budenny were with the Konamiya. Tvheshevsky blamed Stalin for his loss at Warsaw. Stalin had him arrested, tortured, and executed at the start of the 1937 purges.