Why use OllyDbg over standard IDE Debugger?

Recently went for an interview and was asked if I had used OllyDbg before. In fact I have never heard of it, and after looking it up I cant come up with a use case. I am familiar with debugging in general, and used them with various IDE's.

Can some one explain the difference between OllyDbg and a standard IDE debugger and why you would use it?

Thanks

ollydbg is a debugger that is more user friendly
with binaries that do not have source

it is an assembly level debugger it uses heuristics to analyze and provide a better view of the input

ide debuggers tend to be more source level oriented

when you would look at the assembly of an ide debugger what would look like gibberish would be neatly formatted in ollydbg

that is the main use case for ollydbg

a screen shot showing a test.exe (no symbols / debug info / source it is a wild binary) being debugged by visual studio as well as ollydbg

visual studio commandline   
devenv /debugexe test.exe -> f10  
ollydbg commandline   
ollydbg test.exe