Insulating Existing Exterior Basement Walls - The cracks in your basement wall won't generally weaken the structure of your foundation, but they will cause different problems namely, water issues.
When it rains outside, especially if you don't have clean and functional gutters, lots of that water builds up from the exterior of your basement wall. Unless you get regular basement wall fix to keep these cracks closed, some of that water will get into your basement through these cracks. Even if your basement has a leaky valve on all of the exterior walls, a significant enough crack can tear or even shred the membrane and then you're in trouble all over again.
Most such cracks can be repaired from the inside in a cost-effective and timely fashion that does not disturb the soil or what remains of the watertight membrane on the exterior.
The perfect way to execute the basement wall repair is by injecting a growing liquid urethane foam to the fracture. When the liquid encounters water, then it expands dramatically, forcing the foam down and up, inward and outward along the whole length and thickness of the fracture. It dries and becomes more watertight in moments, sealing the crack absolutely. Since it begins as a liquid of roughly the same viscosity as water, then it is going to go everywhere that the water goes. Since it ends up a foam, it's relatively easy to cut off and, if needed, sand down some of the foam that expands inward however usually, that's not a large matter.