Almost all cruising boats have dinghies with gasoline outboards. Maybe one boat in twenty rows their dinghy. We've been living aboard full time, mostly at anchor and mostly in the tropics for going on four years. So we have a few thoughts to share.
If you're going to row your dinghy, you'll need a dinghy made for rowing with good oars and oar locks. Rowing an inflatable dinghy with the tiny oars that it comes with is vastly more difficult than rowing a proper rowing dinghy. Inflatables have hull shapes designed for plaining while rowing dinghies have displacement hulls. Longer oars with shaped blades give you much better power.
The big difference between rowing and an outboard is mobility. With an outboard you're going to get further. Sometimes are places that doesn't amount to much, but in some places that is a big difference. We've been sitting out weather and illness in the Blue Lagoon of the Yasawas. Supposedly there is a farm where we can buy vegetables and eggs just over a mile away. Instead of going there we've been worrying about running out of food before we get good weather to return to Vanua Levu.
The other considerations are minor, but they lean against the outboard.
For us, the biggest factor was that outboards are dirty and stinky. We don't need that pollution.
We don't get a lot of exercise. When we are cruising, rowing is most of our physical activity.
Putting an outboard on and off of a dinghy is a lot of work.
Outboards are also expensive. They cost thousands up front and take more than their share of maintenance.
As outboards are expensive, they are targets for theft. People talk about dinghies being stolen, but typically these stories end with the dinghy being found the next day with the outboard gone.
Both outboards and gasoline take up a lot of room, which some boats lack.
As we don't have an outboard, we have no gasoline on board. This makes us feel safer from fire. However, I have to recommend a small portable generator for anyone thinking of living off the docks. We would have one if we had gas on board, so this point cuts both ways.
We have a sail for our dinghy, which we hoped would add mobility. So far we have found this less than satisfactory. Most of the time the distances are too small to make setting the sail up worth the effort. Most of the rest of the time the winds aren't co-operative. By the very nature dighy trips are out and back, so there is going to be an upwind leg, unless there is no wind and you can't sail. Waiting for weather to sail your dinghy will try anyone's patience.
Overall I can't recommend one way over the other. We're glad not to have the headaches that come with an outboard, but sometime it would be nice to be more mobile.