It's not really that effective, it will protect the leather a bit but it will affect the texture and ultimately is not considered to be best practice for "good" shoes.
If you have a GOOD pair of shoes and want to protect them, the SWIMS shoe covers are solid options:
https://www.swims.com/mens/galoshes/ (However, they are about $125 so you will likely need to be into decent shoes to bother).
Most guys seem to suggest that those are viable options but if you live in a climate with poor weather, beater shoes are a better choice.
Mark