the 'self' as one, static entity is an illusion. we are, at the very least, a multiplicity of selves that manifest and alter in response to our environment. but the selves also inform themselves and are reinforced or reconstructed through our own perception of those selves, our perception of others' perception of those selves, and the act of remembering past selves.

tl;dr self isn't an illusion, exactly, but it's also not just "a useful shorthand for the consensus of all the different processes controlling us."