I am amused at the debate over using briefs. I have read at least one posting that states that the popularity of using briefs has swung back an forth between using few (or no) briefs to using many briefs over the years.
Fact 1: Ward Stone Ireland's original theory had briefs. Not shocking because the pen-and-paper shorthand at that time (mainly Gregg's Shorthand) had briefs for frequent words and phrases.
Fact 2: I have not read through a stenograph machine theory that not use at least some briefs. Some use few briefs like Sten Ed and Robert, Walsh and Gonzalez. Some use a lot of briefs like Magnum Steno.
Fact 3: Hello people, your goal is probably to become a Certified SHORTHAND reporter (CSR). Shorthand means to write in an abbreviated form.
My personal opinion is that frequently used words and phrases should have a brief. After that it's up to the person to decide to write out the word (or phrase) or to use a brief.
If a person wants to write faster, they need to their increase stroke rate (e.g., 3 to 3.5 stroke per second) OR they need to increase the amount of words (or syllables) are written per stroke (e.g., 1 to 1.5 words per stroke).
So, the fewer briefs a person uses the lower the "memory load" (decreasing the chance of hesitation which helps increase stroke rate) but the person needs to be able to increase their stroke rate to increase speed. However, using more briefs means a higher "memory load" (increasing the chance of hesitation which might decrease stroke rate) but the person does not need increase their stroke rate to increase speed.