If value in serial begin is greater than that of delay in arduino, does delay time matters?
The parameter to Serial.begin(speed) is the BAUD rate, or the speed characters are read (and written) from (to) the serial line.  The parameter in delay(time) is the number is milliseconds that the system will wait for.  

I think what you may have noticed is that by experimenting with the Baud and delay parameters you notice that you are receiving characters slower and faster.
The faster the serial line the more data you will receive, but the longer the delay the more the data will be slowed down, because the receive buffer will become full.

If the delay is very small (&lt;50) then yes it will appear insignificant.
Try Serial.begin(9600) and delay(30000). This will show how significant the delay is :)