It seem that the default world container assigns an integrator called "BodySmpEulerIntegrator", for which I can't seem to find the source. In any case, with a name like that I would have two predictions:
a) 'Smp' stands for 'simple' in which case this would be a stock/naive/vanilla Euler integrator. If that's indeed true, then I suspect the answer is that it will NOT handle the transition to SE(n>2), as they tend to blow up when the Hamiltonian becomes at all stiff. That is usually the case for your standard 6N+2 dof system in 3D.
b) 'Smp' stands for 'symplectic', which would make the default integrator some form of symplectic euler integrator. To my knowledge any SI should handle a 3D non-timevariant, non-chaotic Hamiltonian. This seems much more likely, given the amount of effort they've put in. Indeed, if you look at the examples that have a 2- and 3-D version, they don't seem to reassign the integrator.
That's a lot of guess-work on my part, though.
[1]: https://github.com/sebcrozet/nphysics/blob/916199c0a67219482...
[2]: https://github.com/sebcrozet/nphysics/blob/916199c0a67219482...
There is also a explicit method in there, which probably won't handle it very well.
On the other hand, I hesitate to argue with the author about their own code... or are you just the OP?