“Save time”?
How would they know that they were saving time if they had never before written vowels? Doesn’t make sense.
I think they were aware. Papyrus or stone were expensive mediums and leaving agreed upon letters, that does not abandon understanding, would make sense to them. It saves time and money.
A modern version would be what we do when we leave letters out as part of a puzzle.
Phoenician, Hebrew are not alphabets but abjads. Semitic languages (e.g., Phoenician, Hebrew) have a root-based morphology where words are built from consonant roots (e.g., k-t-b for “write”). Vowels often indicate grammatical variations (tense, number, etc.) rather than core meaning. Consonants carried the primary semantic weight, so writing systems prioritized them.
The Phoenician alphabet evolved from Proto-Sinaitic scripts, which were influenced by Egyptian hieroglyphs. These earlier systems often represented consonants or syllables, and the abjad model built on this tradition. Early writing systems, like cuneiform and hieroglyphs, were complex and labor-intensive.
Omitting vowels reduced the number of symbols needed, making the system more efficient for scribes and traders, as the Phoenicians had only 22 characters.
Fluent speakers of Semitic languages could infer vowels from context and their understanding of grammar and vocabulary.
Sentence structure and surrounding words provided hints about vowel placement. Such as verb or noun placement.
I tried learning Hebrew once but gave up and retreated to the familiarity of Indo European languages. My mind could not wrap around Semitic languages.
Of course it makes sense. It is a basic understanding that not doing something takes more time than doing that very same something. Not writing vowels is very different than not writing them.