What is the furthest from the Earth that still offers a total eclipse of the Sun? Is L2 inside that distance? (I assume so due the the halo orbit that is planned but perhaps there are numerous other reasons to fly around the L2 Lagrange point)
However, the halo orbit of JWST will never pass through this region, nor even near it. The operational requirements demand that the telescope never pass through any part of the Earth or Moon shadow.
Additionally, the rather large Halo orbit is chosen to maximize stability, specifically to minimize thruster fuel usage required to keep the probe in the orbit, as discussed here: https://space.stackexchange.com/questions/15167/are-large-halo-orbits-around-l₁s-and-l₂s-preferred-over-small-orbits-for-reaso.