One way to somewhat accommodate Soncino's point is that such distractions in both cases may become a fixation, and thus indeed a sort of obstacle: either in virtue of beauty or attractiveness with Tree and Field (r. Simeon), or because the Marble Stone might seem to be the ultimate source of Water (r. Akiba). The latter would be a falsehood bordering on unintentional idolatry: not "how can we proceed!", but "why would we proceed!?".

That interpretation can further be supported by
a) Hekalot Rabbati 18:2 describes an elaborate technique for terminating a trance which was probably used when things appeared to be going awry. (your ref 3 Enoch, p 233)
b) And the Rabbis? — They were of marble. And R. Meir? — It is hardly possible that the man did not hang on to [the arches] and doze a while. (Yevamoth 121b)