By snake oil machine I am implying that some DI boxes are grossly overpriced. Heck the DI market is starting to even bite into the recording world. They now have DI's that they make specifically for Re-Amping. If you're not familiar with Re-Amping, it is the technique where you record the guitar splitting it through a DI into the DAW and into your guitar amp modeler of choice. When you record you listen to the processed sound of the modeler while the second recording stream is capturing the direct guitar DI sound. You can then go back with the DI track and run it through a guitar amp modeler within the DAW or externally even and have the same exact performance every time allowing you to tweak the amp sounds too perfection.
A DI in its simplest form has about as many parts as you can count on 1 hand!!!!! Some of the active DI's offered by Radial have more parts in it than are on a Raspberry Pi and all its peripheral project modules!!!! Once you break the $100 mark, you are paying for fluff. Some fluff is better than others, but an active or passive DI can be purchased for under $100 and they will perform perfectly fine. When there are DI's asking for a $300= price tag to be paid, you have to wonder how much better that product is vs. another that works just as well and only has $20 worth of parts including the project box.
Di boxes are simple and not exactly rocket science. They work teh same be it for Re-Amping or trying to get your computer into a PA.