I have never seen anyone skip a rung when using a ladder. It is too risky, especially when the climb intensifies. Going rung by rung avoids the obvious consequence if you make a mistake. Additionally, your climb will be steady, consistent, predictable, and very easy to measure progress.
Taking stairs affords the very same benefits as using a ladder. Like a ladder, it is a method of arriving at a destination. But stairs affords the opportunity to be impetuous. If you believe you need to get to a place faster, if you are impatient, or you are only focused on the destination, you will skip very important steps.
The distinction between a ladder and a stairs for training (and life) is metaphorical. The approach that I want you to understand is methodical, mundane, step by step practice establishes the baseline approach for success in BJJ. But, there is an added benefit. By slowing down and going rung by rung, your proficiency, speed, accuracy, and performance will actually get better.
Select any technique or series of technique and identify the steps (or rungs) to fulfill the technique. As you learn and perform each technique, it may take some time to climb the proverbial ladder to get it right. But, as you continue to go rung by rung, the time between each part of the technique shortens. Eventually, it is impossible to distinguish one rung from the next and the technique becomes seamless. Each rung was still used, but the gap between each is what changed. Nothing skipped, nothing avoided.
This approach to learning and training does not address risk, however. This is a different topic all together. For now, in your training, in your development, even in your coaching and instruction: Use a ladder, avoid the stairs.