welcome to the Middle East mate.
I guess the bond will be to cover the cost to convert your licence to one acceptable by the local authorities....thats the official version.
Unofficially ...... the best way to keep you bonded to the company/region
My idea....dont come to the M.E. if the company does not provide you with housing. The market is unstable, unorganised and lawless as far as expats are concerned. You do not want to venture too deep into such an adventure.
All airlines provide housing (even QR).....ask for it!