Yes, I know theoretically D365 is infinitely scalable and can handle any load, but in the real world how many records do you have stored in Dataverse? How many added per year or month? And in high load situations, maybe even how many are you adding per second or minute?
There are people at the organization that are concerned about performance and limits when released into the wild. Just as a benchmark, we're generating over 600k activities/month (so upwards of 7M/yr) which doesn't include all the other reference/product/contact data related to the activities. During peak load we're currently looking at adding around 300 records/minute.