What's the story with the Old Elsay Lake Trail?

I used the Old Elsay Lake Trail to access Mt Underhill today. The section between Goldie Creek and Brighton Beach is a bit bonkers. It feels like the trail builders went out of their way to find the sketchiest route imaginable. I can't imagine anyone using this trail to access Elsay Lake while carrying an overnight pack. Does anyone know when and why (and who) this trail was built?