... and bridge designers don't design 'to have fun', but to have structurally sound, cheap and reliable infrastructure tool to cross rivers. Or imagine hiring a construction company for your dream house, realizing only after all is built that they were experimenting and 'having fun' with new unproven materials, construction, wiring etc.

OP's approach is mighty fine for his own endeavors, but if I had such a worker hired, there would be a serious talk about priorities. If no agreement is found even 100x engineer would be let go.