Even if it has exact same stats it is still better because it is being used on more important targets. As axis your teller mine will hit one out of a zillion allied tanks spam. As allies your m20 mine could win you the game by disabling a panther, jagdp, KT, etc.
Or your M20 mine could get hit by a 222, Puma, Luchs,P4, hell the OKW building halftrack could hit it.
I think the M20 mine is great, but I think being forced into a tech choice to get mines at all is dumb (and a big "BUY SWEEPERS" sign to your opponent)