I think it is meant in the sense of an end of slice signal for example to let an external sequencer choose the next slice without a gap or looping the slice - recording a gate after each slice would not work very well.
Maybe something could be figured out with envelope followers an comparation?
Generally I aggree that the ER-301 should not develop into an multipurpose CV generator.
Also I don’t see much benefit in connecting Ansible via i2c. Everything it can do is already patchable while tletype gives a lot more control slots.