Why do we have Enzymes and not Increase the Temperature?

-Increasing the Temperature will make the Useful Reactions Quicker, but also the Unwanted ones will also Speed up - Not Useful. Cells also have a Limit of Heat until it will get Damaged -Enzymes act as a Catalyst, to speed up Reactions without getting Used Up or even Changed -Enzymes then mean Raising Temperatures would be Redundant, and that Specific Reactions will only be Sped Up -Enzymes is a Protein, which is Coded by Genes.