Why not use malloc S by default?

[minek van]

I gaved it a try, all sets installed, xdm starts X.
after first boot
pkg_add firefox libreoffice gimp
ln -s S /etc/malloc.conf
reboot

all done in virtualbox. 

With or without "S" the 360p testvideo lags.. but virtualbox. 

So tried Firefox, GIMP, LibreOffice

All looks working great. 

So why isn't "S" enabled by default? It is the "most secure" solution for the 
malloc settings, no? 

Or are there still programs that will crash when "S" is used? 

What are those? 

Thanks.