The only case where I'd think it makes any sense is for protecting programming work from simple replication. While it isn't particularly hard to break client-side security bogus, its difficult to turn a minified mess into comprehensible code.
Source code is very effectively hidden by obfuscation.
If that were not true, GNU and open-source and GPL would not exist.
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Regardless, another important thing is not to download source maps onto client's machines, as that defeats the whole point of minification.
Decoding stack traces server-side dedups work and doesn't impose an unnecessary performance burden on users.
Browsers don't download source map files unless the developer tools are opened. If your client is using your app with the dev tools open you may have other problems that have nothing to do with performance.