One thing here is that it suggests removing pure virtual functions with just one implementation. I use this pattern often to kill dependencies, say when one hug

One thing here is that it suggests removing pure virtual functions with just one implementation. I use this pattern often to kill dependencies, say when one huge part of an app needs to call another one, but you don't want to create a dependency one way or the other. In C++, compile times sometimes explode if you include every header in every other one - so it's really great when you can #include just a one-line generic "virtual" callback interface from two places instead. But yes it affects binary size just a bit.