is a preamp needed if I am playing music from a pc?

In the good old days, we had sources like turntables, tuners, cd players that generated low voltages. You wanted to control the volume and modify bass and treble. OK, separates consisted of a preamp and an amp.

Today, our music is in lossless files with resolution exceeding the analog formats. The data sits on a hard disk somewhere. The pc reads the data and can adjust the volume as well as perform room equalization. The pc then  sends that digital data through a usb port or an I2S interface to a dac which converts it to analog. some dacs have volume controls as well (Gustard X20). Analog output from the dac can go directly to the amplifier. 

For those of us who do not have cd players, tuners or turntables, is there any benefit to a preamp?