In the past, Sigmund Bloom would have a lot of conversations about fantasy football rankings. There's value to a linear set of rankings based on statistical modeling. It's the safest way to create a blueprint for a draft.
There are also notable gaps with this format. Rankings are harder for the user to see the draft with as broad a perspective that tiers offer. Not that you can't look at various possibilities at one time with a vertical list, but tiers make the decision-making tree of long-term cause and effect easier to see.
Most rankings based on statistical projections don't incorporate the value of upside. Willie Snead and Mike Gillislee might be within five picks of the other, according to an ADP list or ranking, but the potential for Gillislee to produce fantasy-dominant scores as a red zone threat is much higher than Snead. Terrelle Pryor and Michael Crabtree's ADPs are within five spots of the other, but which one has the most potential to become a top-5 fantasy receiver? I'd argue Pryor.
Then there's confidence factor. A fantasy owner or analyst may have DeAndre Hopkins among his top-15 receivers based on projections, but when asked about Hopkins they may also tell you that they are so concerned about Houston's quarterback situation that they pass on the Texans' receiver in every draft. Or, like me, you might like Falcons tight end Austin Hooper's potential so much (even if you can't truck with the idea of projecting production that, like me, places him as a starter on your tight end board) that his ADP of 154 factors into your overall draft strategy.
Straight up and down rankings lack a lot of valuable contexts. It also creates a lot of layers of conventional thought that promote barriers to taking players that you really want on your team. Some barriers are healthy, because the logical thought baked into the rankings process helps you realize that some of your views are too impulsive or risky for the good of building a team.