What you need to be concerned with is whether the ruler can accidentally under the foot (too thin of a ruler) or if the foot can go under the ruler (too short of a foot profile).
You are safest using a ruler foot (taller profile) with a 1/4" ruler. Any other combination does risk knocking the machine out of timing, breaking the needle, damaging the needle bar, and/or breaking the ruler. You can be injured from some of these things breaking.
Will a regular foot work - if you are very careful. But one slip-up can cause an unnecessary expense in machine repair and there is also the risk of personal injury.