[salawat]

That's defense in depth as applied to system design. Think of it like cleaning out a cat box, and only having bags with holes. You only need a couple bags whose holes don't line up, and you're good to go.

The simpler they are, the easier they are to learn. The easier they are to learn, and less "opinionated", the less resistance they tend to build up against adoption.

D is interesting, because it seems, from my experience, D, like Ada, has been a hypeless language. Though I haven't checked on licensing encumber meets that might be behind that.