Those who have studied the German oracle decks will know they are related with the Lenormand being older than its Bavarian cousin. I cannot speak for others reasoning but will share here my means of selecting what deck to use and when.
Lenormand is a symbol deck.
I use it primarily for issues related to dream work, checking energy evaluation and alignment in magical practices, interpretation of mental cliches such as daydreams and visions and in working with non-corporeal intelligences. Lenormand therefore is used by me as a divination deck, a translation device, to interpret the signs seen in the physical and spiritual realms and express them in the concepts of human language.
Lenormand small layouts are limited either the lines of 5, 7 or 9 or the 3 X 3 Box Spread. The Grand Tableau suits the lenormand deck best putting out all 36 cards.
Kipper cards on the other hand are situational.
They contain scenes which are part of mundane life which everyone can recognize. Kipper is a great selection for clients who want their fortunes told, i.e. to see the causes and effects, motivations and directional trends of themselves and the people in their immediate environment.
Kipper has more variety in the number of traditional smaller card layouts which do not place all 36 cards. It can use the Grand Tableau but due to alternatives is not as dependent on it.
Which deck do I use more frequently ?
The answer is the lenormand. This is due to my familiarity with Lenormand symbology, since I am prone to use a 5 or 7 card line when looking for an answer on projects I am working with.