It will depend upon your state laws as well as the terms of your insurance policy whether a repair to your windshield is enough or if it should be replaced.
In many states insurance companies can indeed decide to repair the windshield crack or chip or replace the whole windshield. If the windshield crack can be repaired, which is usually done with a specially formulated resin being injected into the damaged area and then the resin cured, then an insurance company may choose to do so since it is a cheaper way in which to take care of a small windshield problem.
A good repair job to the windshield should restore its structural integrity and restore clarity to the area so your vision is not impaired around the area which the crack was. If after the repair your vision is still impair in the area of the crack then a glass company will normally decide that the glass should be replaced.
Repair jobs are cheaper than replacements and thus one reason they are used by insurance companies for small cracks or chips. Also by repairing instead of replacing the windshield the integrity of the original factory seal is not affected since the glass is not taken out and you keep your original manufacturer quality glass in your vehicle.
To see what state laws are regarding insurance claims and your front windshield contact your state's insurance regulatory body. If your insurance company wants to repair the windshield it seems as if your state allows this. You can also read through the terms of your comprehensive coverage to see if it speaks about repair versus replacement of glass on your vehicle.
As for making you whole, this phrase is normally used if your car is totaled out and an insurance company is offering you actual cash value and are "making you whole." For windshield claims they normally want to make sure your vision is not impaired and the structural integrity of the glass is not compromised which in some cases may be done with a repair instead of replacement of the windshield glass.
A glass repair / replacement shop will be able to tell you if your windshield can be repaired or if the type of crack you have needs the whole glass to be replaced. If it can be repaired then you may want to see if it is worth making a claim or if the cost of the repair is less than your deductible. Also sometimes an insurance company will waive the deductible if your repair your glass instead of replace it so if you choose to go through your insurance to get the windshield crack repaired you may ask about having the deductible waived.