It wasn't impossible, just difficult because the heavy cast put me off balance. And then there was the fear of falling again on the painful ankle. I was glad to be free again. Oh, I've met people who feign strength to the outside world, but inside they often feel very small. I also know people who have been snared by life's traps and damaged by abuse who need to recover and become healthy.
Crutches keep the weight off the damaged limb until it is healed.
If you try to get well without protecting the hurt from further damage, you end up deformed for life. Alcohol and drugs are a popular crutches. While they don't provide protection from the damage, they obscure the pain for a while, but the cure can be worse than the cause. Another crutch might be denial of the reality of pain itself and escape to some psychic detachment. And then there is Jesus.