Do you do your own draft list? If you just grab the overall ECR list and take it to your draft, read no further. But if you make your own draft list, then mock drafting is an essential part of refining and perfecting your draft list.
The purpose of a draft list is for it to work as deep into a draft as possible. If it becomes worthless after the 4th round, then it needs some work. If you can ride it through 10 rounds or more, you’ve done some seriously good work on it.
Perfecting the list is where the mock draft comes in handy. So you’re in a mid-round, and you have a tier 4 RB that you don’t need or want, but there’s a tier 5 WR that fits your needs well, plus you really like him? Of course you’ll take the tier 5 WR, but that also points out a flaw in your list. Time to adjust it. Whether it means dropping the RB into tier 5, or raising the WR to tier 4 is up to you, and you need to practice it to see how it works either way.
Regardless of how good your draft list may be, NEVER treat it as gospel! Circumstances always dictate how you draft. But with a great draft list, you can still handle the “slings and arrows of outrageous fortune”!