Ask HN: How to Explain the Cloud to Nondevs?

I'm in biglaw rn and may need to explain to lawyers why there is nbd about using normal cloud-based SaaS software as opposed to the usual garbage dotcom era software they use, where the company seemingly runs their own servers sonewhere.

What would you guys say under such circumstances? As a dev who never coded pre-cloud, I'm not even sure I know the diff well enough to fully explain. It's mostly about devs being able to easily scale horizontally and vertically via an easy protocol, as opposed to provisioning each machine, right? And sharing machine space between customers who don't know each other?