Were there other benefits at all to keeping the SM attached? Did it have residual supplies that were of use?
Meteorite protection?
I think you mean "meteoroid". A meteorite is the remains of a meteoroid that has fallen to earth as a meteor.
The early Apollo literature is full of analyses of the potential hazards of radiation and micrometeoroids. We've talked about how they mitigated the radiation hazard, such as trajectories that passed through the Van Allen belts at high geomagnetic latitudes and frequent dosimeter readings.
The spacecraft were also designed to resist small micrometeoroids. The CM had a lot of inherent protection from its relatively thick heat shield and double-hulled structure, so the heat shield wasn't at much risk.
But the LM's severe weight limits required something more clever. The ascent stage used "Whipple shields": thin sheets of metal held by standoffs some distance from the pressure vessel. (This also created a space for aluminized Mylar or Kapton thermal blankets.)
The idea of a Whipple shield is that a small micrometeoroid hitting the outer shield will still puncture it without losing much kinetic energy, but it will fragment into many smaller pieces that spread out and hit the inner wall in different places. The inner wall thus has a much better chance of withstanding the strike than a direct hit from the original object.
As it turned out, micrometeoroids simply weren't a major problem in translunar space or on the moon for the short duration of an Apollo mission. There was also far less debris in near-earth space than there is now.
