Scientific notation is shorthand for writing really big or really small numbers. Without it we could not do certain calculations because there would be just too many digits and it would be tedious.
For example:
writing out the numbers in standard form..
1,440,000,000 ÷ 0.0000012 = ???
= 1,200,000,000,000,000
Scientific notation...
144×10^7 ÷ 12×10^-7 = 12×10^14