cryptography – When should I use CryptoPP :: AutoSeededRandomPool (not CryptoPP :: NonblockingRng)?

I found cryptopp provides several random generators: CryptoPP :: AutoSeededRandomPool, CryptoPP :: AutoSeededX917RNG etc. I know some details about these generators and their use, I wondered why I needed them?

CryptoPP :: AutoSeededRandomPool and CryptoPP :: AutoSeededX917RNG default base on CryptoPP :: NonblockingRng on what basis / dev / urandom. Many articles have told me the / dev / urandom is secure enough and suitable for all (almost?) scenarios, so why use DES / AES encrypt the data read from / dev / urandom (which much slower)?

When should I use CryptoPP :: AutoSeededRandomPool or CryptoPP :: AutoSeededX917RNG?