An incorrect notion that you may come across on old internet postings was the idea that the ESQ/SQ80 envelopes were "slow". As you can see from this table, it would be possible (at minimum settings) for the synth to complete an entire envelope cycle in point-oh-forty-four milliseconds. --Half that, really, because only the attack and decay stages are necessary for the most rudimentary type of envelope.
It's likely that the "slow" rumor got started by someone who didn't understand the envelopes as well as you do (now that you've read this webpage). The idea may have been parroted around the review boards by lazy or uninformed posters. Indeed, you can find a few postings from people who have delved deeper into the synth to discover the envelopes to be quite responsive.
If 22 or 44 thousandths of a second is too slow for you, then your musical ear is working at an entirely different level than mine. It's no coincidence that the 11 millisecond step time we are talking about is very close to the 10 millisecond unit of time known as a "jiffy". Maybe in the future someone will come out with pico second-accurate envelopes for you.
Some have questioned why the zero value for the envelope is 11 milliseconds and not, well, zero. The reason is that an envelope, by definition, must occur over some span of time.
It would make no sense for an envelope to evolve or change in "none-time". Indeed, this “capability” would essentially constitute no envelope at all, or at least not the kind of change that an audio/filter envelope is designed to modulate.
The creators of the ESQ/SQ80 series probably decided on the 11 millisecond minimum based on a logical division of the timer circuit. [The previously-mentioned 10 millisecond "jiffy" is the cycle time for a frequency of 100 Hz . So you can quite literally do the math... ]