One of my old bosses loved to do catering events with 'food on the stick' as he called them. It is really convenient for parties, even though can be labor intensive if we are talking about a party for a couple hundred people...
But if you plan and built the spears well, so that the weight is evenly distributed, the spears are not too heavy, and the items on the spears are not 'dripping' too much, this is a great way to serve tasty, colorful food, with a little flair, on the summer parties. With some planning and careful construction, you might be able to just use large, heavy duty napkins, instead of plates and cutlery. Great to remember, when planning a party.
Since summer weather is always unpredictable, planning an outside party has it's risks. At least up here. But the items put on the spears can be done in the oven as well, on the stove top, or on the grill. If you grill the spears, ready constructed, make sure your pieces are evenly cut, takes about the same time to be done, and have a little space between each other, so that they will be fully cooked. Also, remember to soak the spears in water, before putting the food items on them, so that they will not catch a fire, when put on the grill.