The network lines that carry data around the web have a finite capacity. There is a any limit to the amount of data that can be transferred at any point in time.So bandwidth can play an important role?
The hard drive of a web server has a limited amount of space determined by the physical size of the hard drive. Both are commodities which costs money. So it impossible for any company to provide unlimited bandwidth and diskspace.
Most websites on the net only consume a very small space of bandwidth and disk space. So they doesn’t concerned about bandwidth.