I recently observed this hand:
RHO opened one club in 1st seat and this hand overcalled one diamond. That’s an overcall that has nothing to gain and much to lose. It’s a lousy nine point hand. It does not interfere at all with opponents’ search for a golden major suit fit. It encourages partner to lead a diamond if LHO becomes declarer, ugh. Sure enough LHO became declarer and parter led a diamond, giving the opponents a top board.
My recommended partnership agreement is that a one diamond overcall be lead-directing with at least an almost opening hand. Overcalling with the junk above leaves partner with too much guess work about whether to compete or double for penalties.