This is often better than starting from scratch, as it reduces premature commitment to a fantastic-sounding idea.

Yes, there is a danger of that, certainly. On the other hand, if you start from what works for meat beings then there is a danger of being stuck in a local optimum. Probably both ought to be explored, and I am not sure if one or the other ought to have precedence. My personal opinion, admittedly not rigorously quantified, is that failure of imagination is a worse sin than reinventing the basics when dealing with predictions. But then in my physics studies I learned the importance of always being able to rederive the conclusions from the first principles, not just from half-processed expressions with potentially a lot of hidden or forgotten assumptions built in.