The issues with search start emerging as code base grows in size. For instance, in any decent sized C++ library likely has multiple definitions of functions, to be compiled with different compiler flags. In a simpler case, you might even have overloaded functions with different signatures but the same name.

The value with IDEs is a smarter method for traversing code. It figures out exactly which function you mean, helping you get better context cues, auto-completion and traversals. This isn't particularly easy to emulate through simple command-line tools.

I use atom and use searching all the time too. Mainly because its so easy to reach and execute trough shortcuts. Definitly faster than touching zhe mouse.