Biofuel is a renewable resource. It can be a fuel-hog, you've already got the infrastructure in place to provide it.
And that's assuming you've got a 36 HP boiler up to 100% which takes... what, four or five hours game play? During which time it will be significantl less fuel efficient. It will take days of running nonstop at 100% to hit the break-even point, of consistent play. Unless you've got a 24/7 server, that's not going to happen any time soon. Which means your so-called advantage is going to be a detriment in most actual game-play situations.
In exchange, they produce 16 MJ/t in a single block. Therefore, 10 of them will outperform a boiler and its full compliment of engines. Hell, just the generators themselves will take up less space than the industrial steam engines, much less the damn boiler! And don't even get me started on construction costs...