The thing I miss about Secure Empty Trash is the ability to delete a stubborn file in your trash. Say that you delete trash, but it stops because there's a file in the trash that can't be deleted. In Yosemite, you would just then select Secure Empty Trash and it would delete it anyway. I'm not sure if there's an equivalent in El Capitan.
That is the main reason I use secure empty trash- stubborn files that won't delete from trash.
Maybe there is a command line for this or some other alternative?