Erm... no? I'd hardly call this a "knockoff", it has some interesting ideas that I haven't seen anywhere else. Namely:
=limiting the buttons you need to press to just two; most DDR-likes have four buttons (but there's some exceptions)
=a huge swath of "beat" types; most DDR-likes only have "hit" and "hold", whereas this game has lots of different types of things. (Admittedly, some are better than others)
=switching up the visual indicators for the beat types, i.e. whenever the screen transitions.
But even if it was a typical run-of-the-mill DDR clone, I'd still say this has value. Its beatmaps are (mostly) really solidly designed, the visuals are good, the audio is great, and the execution is just really great in general. Saying that two games with the same concept are virtually identical is like saying a Jeep is virtually identical to a Ferrari (both of them are cars, right?).
(Also, if you think this game ripped off Friday Night Funkin', then... I recommend doing research into Dance Dance Revolution, though you might not like what you find).