Irrelevant comparison. A good analogy would be... to read Anna Karenina syllable by syllable. If you really love Tolstoy, you'd spend fifteen minutes repeating each syllable mindlessly, to get it engraved in your ear. Right? No.
What you are developing is an entire musical composition, a strucuture which spans hundreds or thousands of measures, from the first to the last. We don't even think of how many measures there are... usually instead we think in terms of phrases, sections, movements, colors... Quite often a single note or motif might be crucial to this, and worth spending hours and hours to develop. Or a technique might be particularly elusive, or demanding, and hours of creative practice is needed to bring that section up to clarity.
...So there's nothing wrong at all with spending hours, or years, on a few notes in sequence. But to do this systematically, to go through repeating each note in sequence before progressing to the next one, is a complete waste of time.