First of all, in the 40+ years I've been on stage I've only used about 4 self-working effects, usually for radio gigs. The exception is found in my PSYCHIC HOT-LINE routine in which we tossed in a couple of self-working bits for my partner to do with the audience. Regardless, self-working effects are, on so many levels, superfluous and rarely practical for anything more than a bar bet setting.
Secondly, if slight-of-hand were such a non-requisite it wouldn't be amongst the first chapters found in the Mark Wilson & Tarbell Courses of Magic let alone the famed Bill Tarr "Now You See It;Now You Don't" series; the Wilson & Tarbell texts arranged with a rating system that allow the student to start with the simpler moves & techniques and progress according to his/her ability, over time. Then again, I've never seen a single child's Magic Kit that was full of self-working tricks, most required rudimentary slights and basic magic theory so that you could execute the Snapper, Ball & Vase, Cups & Balls, Pea & Shell, Multiplying Bunnies, Linking Rings, Professor's Nightmare and a plethora of other such "stock" effects such kits included and have included for over 100 years (just check out the Copperfield collection if you don't believe me).
You are correct in the fact that showmanship and presentation are paramount, it can make a shoddy performer shine brightly but at the same time, it can keep that same shoddy performer from stepping up to the plate and actually learning how to do the work. I've coached far too many poor-little-rich-kids over the years who's mommy & daddy dropped a half-million bucks on a John Gaughan-Bill Smith Magic kit and yet, Jr hadn't a clue when it came to how to actually work on his collection of neat toys let alone anything about the nuance when it came to operation or how to adjust things so as to enhance deception and improve performance. Owning the prop doesn't mean you can perform it and the philosophy you are encouraging here, encourages that type of lethargy -- the lack of self-application and the constant quest for the easiest way out.
Magic never was based on "easy" when it comes to how to execute an effect, but rather it was based on discipline and doing what it takes to "get there".
When my mentor was taking over the Thurston-Rock show in the early 50's there was one particular effect he wanted to learn above all the other wondrous stuff in that stock-pile of famous effects; the Orange Bowls.
Chances are few that are younger than I have ever seen this uncanny effect in which two simple music-stand type tables sat on stage left & right about ten feet from one another. When first seen there is a laced doillie covering the table top with a glass bowl on top and within this a cloth napkin. The mage lifts the bowl and in a slow, very deliberate manner, dusts it clean with the napkin. He then lifts the lace table cover to show an acrylic top. . . everything completely clean! The bowl is sat back on the table with table cover & napkin dropped within. . . these same actions are replicated with the 2nd bowl and all is seen as fare. . . until the see through cloth is removed from each bowl and the bowl is found to be over-flowing with REAL oranges, every one of which are tossed out to the audience. . . nearly 3 full pounds of fresh oranges.
I emphasize "real oranges" in that the Abbott Magic company make a cheap
knock-off to the effect that was mechanical and used foam oranges with just a couple of real "convincer" fruits.
This was the very last bit Will Rock would teach my teacher because it was the thing he wanted most to know. . . because it was the secret he needed to EARN by proving himself with all the other material first.
The Orange Bowls are "simple" when it comes to the mechanics and yet, one of the most difficult effects out there when it comes to pulling it off and making it impossible. One must literally become that actor playing a part in order to sell this masterful demonstration in pure slight-of-hand. Granted, you could buy the Abbott "self-working" version and not have to invest yourself into doing what's required for delivering quality -- an actual expression of personal pride as the result of practice and accomplishment. But then theres the rub, isn't it? The short cut sells you short and causes your magic to be just as limp as you are because of seeking out the easier, softer way which is rarely what we think it is. . .
. . . then again, learning of the Fool's Journey and how it ties to the Tarot, might open one's eyes a bit further when it comes to this challenge.