I have come to the conclusion that it is best to not use it as a slide release. It will usually work just fine in that role, but I think it was not intended for it. I believe Browning's intent was probably that we use the rear gripping groves on the slide to disengage the slide stop by pulling the slide all the way to the rear and sharply releasing it.
It will usually work fine in the role? When won't it?
I believe Browning's intent for the rear serations was primarily for the initial charging the pistol and that they can be secondarily used as part of the slide release system.
I do use the slide stop as a slide release, and I'm pretty sure JMB designed it to be used this way. Why else would he have put the checkering on the top surface and none on the bottom surface?
It was designed to work either way.
People keep talking about what the 1911 was designed to do such as with the slide release or with cocked and locked carry, but nobody has any design notes from JMB saying things one way or the other. It may work fine in either capacity, but saying it was or was not designed for that is a bit iffy without documentation.
Seraph's reasoning is interesting. If we were to follow the logic, then it part is NOT to be used to manually engage the slide because there is no checkering on the bottom. Even if the checkering on the top is for the part to be used as a slide release, is it that way for use all the time or was this simply an emergency feature designed into the gun for one-handed operation, if needed, in a critical situation? Parking brakes can be used as emergency brakes on cars, but that does not mean they are meant to be used as emergency brakes on a regular basis.
The point here is that design intent can be argued both ways. We don't know the intent by JMB or even if this was JMB's intent either way or not or simply a positive byproduct of an overly well made part that functions fine in a dual role.
Something to keep in mind is that design intent does not have to be critical or significant to application in cases where a part is over engineering. A hammer may be fine for hammering nails and that may be the job for which it was designed, but it will do a heck of a job as a precision bug smasher. If after over 100 years of Colt pistols with slide stops/releases being used in both capacities, if there was a problem, I would think it would have materialized, especially in the Model 1911 that has been so extensively used.
Many tactical schools are teaching to use the slide instead of the slide release, because of gross motor skills vs. fine motor skills. During high stress, fine motor skills are lost or at least impaired.
Swiping 'off' the slide catch (or swiping 'on' the slide release) is a gross motor skill. It is not as gross as using an entire hand to grab the slide, but it isn't as complicated either.