There are several issues related to this approach for our organization.
Using a button to get to the Glossary means that learners are navigated to a completely different lesson. Learners must remember which lesson they were busy with, and then manually find their way back to where they were before jumping to the Glossary. This may sound like a trivial thing to do, but we have some very large courses with more than 100 Lessons.
As the Glossary is a Lesson, it becomes a problem for us as our course completions are based on the percentage of the course viewed. The Glossary Lesson becomes a part of that percentage and learners that do not need to view the Glossary, may have problems achieving course completion status.
At best this is a workaround. For a Glossary to be effective, it needs to be a Globally available resource that can be opened, viewed and closed without the learner being required to physically navigate away from their current Lesson.