I started teaching in higher education organizations when I was still a student. That was more than 20 years ago. I’ve never stopped since then. I’ve taught in different kind of organizations (i.e. engineering schools, universities, and applied science schools) and two different countries, France and Switzerland. A common trait among all those jobs was the requirement to teach on-site. In fact, my current employer goes to the point of specifying it explicitly in its regulations.
Whatever the side of the fence you’ve been on in trainings - teacher or student, I believe we all share the same experience: it’s very hard to stay focused during a couple of hours. This has only become worse in recent years, with mobile phones being a huge source of distraction. The consequence is that the most important part is the practice.