It's certainly set up to do so, you can choose your signal path routing and level as needed. We have used it at the factory for some of the demo video content, so yes it does work.
I've used it for pre-production tracking. I ran it post-eq, was happy with the results. When I go back and do the tracks again kind of a toss-up whether I use the WD-800 or my Mike-E rack preamp.
Tell you the truth, I really haven't yet inspected the rear of the amp ... I didn't notice the DI.... thanks for that. I'll have to look into it. I did notice a spot for plugging in your coffee maker, it does make a good pot of coffee as well as kick out some bass goodness.
I do not use the WD but use the Genzler Magellan as just a DI in cabless situations straight to the PA and for live recordings often, as they have the same feature set and DNA in regards to the DI I will say it works fantastic for recording and live to the PA. Use it set to PRE and have a great clean just your bass tone on par with the best DI boxes made. Set it to POST and twiddle your knobs to your ears and hearts delight.
Following up - I've been using the WD-800 pre-EQ as a DI on the recording we're doing and it sounds great.