Tradition becomes defaults, and defaults matter.

I personally switch between at least 3 different editors, and wind up reading code semi-regularly on at least 5 different machines under a number of accounts, some of them shared. Every one of those editors and machines has a default tab stop of 8, and my life is too short to worry about changing them all.

With space based indentation, I don't have to care. I also don't have to try to convert everyone around me who uses space based indentation (and some of whose editors are stupidly set to compress code by turning 8 spaces into tabs). All in all it makes life far nicer for me that the codebase I am working on is space indented. (With some tabs whose presence is invisible to me, because I leave the tab width alone.)

Therefore to me there is a slight advantage to space basd indentation. And there is a huge advantage when it comes to not having to fight the whole world.