Stall strips vs. Washout

Stall strips are used to fix a design shortcoming. No engineer
wants to design a wing that stalls sooner than absolutely necessary,
but some wings didn't behave as predicted and the stall strip was meant
to induce stall on the inboard wing areas and get the nose to drop
before the ailerons lost authority. The Tomahawk has a reputation for
some nasty stall/spin behavior, and I imagine the stall strips were
meant to alleviate it somewhat. The Bonanza has them, too. With newer
computer-generated airflow modelling it's easier to spot deficiencies
before the wing is built.