Here's a reason: I have two GMC Zenith carbs on my 235. Over a period of weeks not running, the gas evaporates or leaks out of the float bowls. Then, to start it I have to pull an air cleaner and prime the carb with a little gas. What a pain! So I bought an inline electric pump at the swap meet and installed it in place of the mechanical pump.
Problem solved. That is until the alcohol in the gas ate up the plastic insides of the pump and I was back where I started.