My Philosophy
Adding the audio option to Computer -Based Training courses improves the retainability of the information being provided.
I record my own voiceovers not just for the courses I created, but also for the courses created by my fellow designers.
However, the new Neural voices in Storyline, combined with SSML coding, make the voiceover recording obsolete. So now I only use the neural voices in Storyline and for Adobe's Character Animators.