Pegging the splice of a half sole on a shoe with a welted waist is just a critical as on the half sole applied to the pegged waist.
The whole issue of half soling a pegged waist is in not disturbing the existing pegs because re-pegging simply makes more holes. So the fewer times you do a full sole the fewer times the pegs will have to be replaced.
Beyond that the pegged waist is probably more stable than the welted waist...not always, but often...so there is really less, not more, rationale for pegging the splice on the half sole than on a welted shoe.
But having said that, the splice on any half sole really ought to be secured with more than cement and peripheral stitching...esp. since sole presses and press cement went out of style. So it's either nails or pegs...and, when it comes to that, it doesn't make any difference whether the waist is pegged or not, it needs to be done to ensure maximum life and utility from a half sole. .