Travelling from canada to kochi.7 hour Layover in Dubai.

Hey everyone, I’ll be traveling from Toronto to Kochi tomorrow, with a 7-hour layover in Dubai. I’m wondering if it’s worth purchasing items from Dubai Duty Free or Kochi Duty Free, or if I could get similar items from Lulu or online? Also, is it a good idea to leave the airport to explore the dubai city during my layover? I can get a visa on arrival.Any suggestions?