Personal opinion here. I like MTB pedals even on road bikes. My reasoning is I get off the bike and go into the quikie marts, and I don't like falling on my a**. MTB shoes can be light weight and stiff just like a road shoe. Just make sure whatever pedal/shoe combo you select works well. meaning, you don't get hot foot. The sole of the shoe is stiff enough you don't feel the pedal coming through your shoe. You can unclip quickly when you need to. You don't unclip when you don't want to.
If you don't get off your bike and walk around in your cycling shoes, you don't walk on tile floors of quickie marts, or have gravel parking lots, then road shoes and cleats make more sense. Again this is just my opinion.