I can't speak for all companies, but many SaaS companies know that its hard for customers to see value from their product until you have some meaningful content in their system - data, users, etc. They could put you into an empty state product, but their own data may very well show that there's a much higher bounce/churn rate or lower conversion rate because its hard for customers to see value vs. when they provide the demo first and then provision access.

I think you'll find some of the MRR sales & customer-success related metrics also cross over into the ARR world:

Sales metrics:
- Length of sales cycle (# of days at each sales stage)
- # leads / week
- # of attempted calls / week
- # of completed calls/demos / week
- # of deals closed / week
- # of lost deals / week
- Close rate
- Customer acquisition cost

Customer success metrics:
- Renewal rate
- Upsell rate & value
- Utilization rate
- Lifetime value
- NPS