Sure, but “effectiveness” is usually not a binary and is often difficult to measure. Small, but persistent changes should still add up. Eventually.
So long as people recognize that these things are in fact quite toothless, I’m not sure they are entirely detrimental. There’s no reason this couldn’t be used as a starting point for more effective action, now that signatories are in greater contact with the campaign.
Only just recently?
Line goes up in relation to how successfully the corporation pursues the agenda of those with power (read: money).