FWIW I have an Octratrack and a Zoom h5 and I love the Octatrack but I use the Zoom H5 a LOT more, so putting aside differences between the OT and the Digitakt, there’s a LOT to be said for having an H5. Even just being able to go out and make easy field recordings of decent quality with it opens up a whole world of possibilities regardless of what sampler you end up with.
A portable recorded is a lot more than just something to record your hardware jams on (although it’s great for that too - I’ve got a pretty decent interface on my DAW and I still regularly record to the h5 because it’s so convenient and sounds good enough).