I'm another who used "mountain" pedals (Crankbeaters Candy SL) on my road bike, along with Keen sandals. Loved being able to get off the bike and walk around a market. I used to use Speedplay X series back in my serious road-riding days, and those were a pain to walk in! So, no, I don't think your LBS guy steered you wrong at all.
Emily
2011 Jamis Dakar XC "Toto" - Selle Italia Ldy Gel Flow
2007 Trek Pilot 5.0 WSD "Gloria" - Selle Italia Diva Gel Flow
2004 Bike Friday Petite Pocket Crusoe - Selle Italia Diva Gel Flow