Why does Tezos use a follow-the-coin strategy for the random selection of bakers? Couldn't the following simpler procedure be used? Take the total owned stake t, sort delegates by their stake, draw a random number between 0 and t, and sees where this number falls in the sorted list of delegates.
The follow-the-coin strategy is described in the Tezos white paper (in section 3.2.4) and is an adaptation of the follow-the-satoshi algorithm developed by Bentov & al.
In essence the reason is a security question with regard to how difficult it is for an attacker to assign herself more baking rights than average. Here is an excerpt from the motivation section
Motivation This procedure is functionally different from merely drawing a random address weighted by balance.
Indeed, in a secretive fork, a miner could attempt to control the generation of the random seed and to assign itself signing and minting rights by creating the appropriate addresses ahead of time. This is much harder to achieve if rolls are randomly selected, as the secretive fork cannot fake ownership of certain rolls and must thus try to preimage the hash function applied to the seed to assign itself signing and minting rights.
