why are isotonic solutions used as parenteral solutions?

why are isotonic solutions used as parenteral solutions?
~I'm stumped, but I wear isotoners because Dan Marino hypes them.
we use hypertonic and hypotonic solutions as needed by patients. for hyperalimentation, we use high percentage of dextrose to provide nutrition, and for some patients near high amount of sodium surrounded by their blood we use 1/2 NS or .45 NS, so yeah we dont use isotonic only for parenteral use. hope this is kind.
Isotonic solutions are used because they have similar electrolyte concentrations and molority to conventional plasma. These solutions then do not alter the electrolyte concentration as much as hypertonic/hypotonic solutions and also stay next to in the vascular system longer due to the molarity human being similar. The other solutions will cause ooze out of the vessels or within the vessels.
There is a use for hypo and hypertonic fluids but on the most portion isotonic solutions are used.