The difference is that Arduino interfaces the electronic world; you need to know your domain.
I've been designing electronics and firmware professionally for my entire career. Right now I'm acting as a consultant developing a network-enabled industrial device. It's going to be powered by an Arduino simply because it's easy to do, robust enough (after I design appropriate power supply protection), and most important: enormous amounts of documentation and experience in the community means I can probably complete the entire project in less than a day of work.
That's what matters. Not some mistaken concept of "gentrification" because you're pissed off at opening up your Good ol' boys club.
That makes absolutely no difference. You can still be a bad engineer.
If you find Arduino bastardized C++ superior than AVR-GCC, you are a poor developer. Everything you can do with Arduino C++ wrapper you can do with normal C++. You'll save resources, end up with firmware, written in industrially standard language, will have better control over hardware.
> experience in the community means I can probably complete the entire project in less than a day of work.
If you after "designing electronics and firmware professionally for the entire career " still need assistance from the community for already well-documented 8-bit controller, it tells about you.
> pissed off at opening up your Good ol' boys club.
No, I am not - after all I am not an embedded developer; I am pissed that it is advertised as something it is not: not a good tool for making industrial automation, not a good tool to stay with if you decide to get involved with automation seriously. It gives a wrong idea to the student about how AVR works, it locks you in with the platform and at the same time dominates the sector.