[user5994461]

There are very few justified usages that require to write maze of rewrite rules.

Most people do it because they have no idea what they are doing and they never decided on a naming convention for their apps and domains.

[Something1234]

What are some justified uses of rewrite rules?

[tyingq]

Making broken links pointing at your site work (301), without breaking links to the correct URL.

Especially links on sites you have no control over.