There are 3 major benefits to the secure hashes that we use, such as SHA-2
1. A hash tells you nothing about the file it came from.
Some hashes contain clues about the length of the input file, but otherwise it's essentially random noise.
2. If two files are similiar the hashes have nothing in common.
For example the SHA2 hash for "This is a text." is
while the the SHA2 hash for "This is A text." is
Similiarly: if you could find two similiar hashes, that wouldn't say anything about the source files.
3. If two files generate the same hash, they must be the same file
Given a hash, there is no way to build a file that will generate the same hash better than trial and error. For the SHA2 hash, it would take an average of 57,896,044,618,658,097,711,785,492,504,343,953,926,634,992,332,820,282,019,728,792,003,956,564,819,968 tries. Which is to say if every person on earth tried a million files a second, it would still take 262,093,447,154,870,433,703,503,188,873,629,081,464,828,682,402,716,927 years. This is the kind of thing we mean by essentially impossible.