Earlier the focus have been on how they could train the learners on certain topic. With the skill based learning that focus is on how that topic can help users develop and learn certain Skills.
With summative testing a learner who has 80% in an evaluation may have an 80% mastery of all learning outcomes or may have no mastery what-so-ever of 20% of the learning outcomes. Further, this student may be permitted to move on to higher learning and still be missing some abilities that are crucial to that higher learning.
A student who knows most traffic laws and has mostly mastered controlling a vehicle could be treated equally to a student who has a very high mastery of vehicle control but no understanding of traffic laws, but only one of those students should be permitted to drive.