Why do we need bost-bootstrap ?

BootStrap file:
https://mega.nz/#!JRIQGSqL!O8cS-uTUp8oQj32f7VZm-NMKEQQSzsJzXIuY5qUFq_Q



Why i have in wallet balance 8830 and the link http://explorer.bost.link/address/BDKo54K3YvkhqKGprcFMCHuqKzeWr5eW3H say me i have 9266  



P.S I add bootstrap in .. roaming/boostcoin.. now balance in wallet too 8831 )