I have no problem with computer only courses (that when well done equip the new diver with a way to use a valuable tool, but leave them unprepared for when something goes wrong with their computer), but such courses don't really save any teaching time.
I have never heard of anyone advocating such teaching for the purpose of saving time.
No matter what, one is required to teach at least the basics of decompression theory. That is the same no matter what. In addition, one must teach tables (or the electronic version), computers, or both.
I don't know anything about the SDI program, and I have never taught the computer version of the PADI course, which is an option for the student. I have, however, reviewed the outline of the PADI computer OW course, and it is extremely thorough. The student will come out knowing a lot more than what to do when the computer fails.