In response to powering the pump via coal being trivial the same could be said for powering the boilers with coal.When asking closed-ended questions, the choice of options provided, how each option is described, the number of response options offered and the order in which options are read can all influence how people respond.
http://www.pewresearch.org/methodology/ ... re-design/
Sure people may only use the entity a few times and never use it again when converting to solar, but does that mean it shouldn't be in the game? I can think of a couple other entities used only a few times and never again such as the iron pickax, fish, wooden crates, wooden power poles etc.
In my opinion, Factorio is a game about logistic puzzles that need to be solved...and what better place to put a trivial puzzle to solve than at the beginning of the game?