When you do a Combat Damage Calculator run, you can quickly see how +1 to attack can frequently give 1.5 damage or more than what flat 1 damage would offer. Not to mention, it makes it harder for Sneak Attack status conditions to hit.
So if you play a full BAB class you may get another 2 damage a round or more for every +1 to your attack. By level 10, a full BAB class could have the functional equivalent of another 2d6 Sneak Attack damage without all the rigaramole of trying to set up a sneak attack.
Plus, Rogue sneak attack damage is frequently tried to be accomplished by Two Weapon Fighting. Regardless of the merits of that, it could mean the person playing the rogue has to take even more To Hit penalties. That could be throwing a Rogue's damage per landed attack and damage per round out of the window.
I mean, people say Deadly Sneak is a trap option because taking -2 to your hit when you need to get situational/rider damage like Sneak Attack dice to land can translate to losing DPR. But by being a 3/4 class with no way of inherently boosting its To Hit via class features or spells, every attack is being gimped.
I have felt for a while now that Rogues should get full BAB and +1 to their attacks for every 1 die of Sneak Attack they have. Any d8 or d10 class that does not have spell casting should be given the full BAB and a situational boost to some of its attacks.