[Joker_vD]

Yeah, turning 1 bit of plaintext into 20 MB of ciphertext kills any hope for "reasonable speed". I have a toy functional language implementation that has no built-in data structures whatsoever, and even it in the end represents a bit only as an 8-byte closure.

[ssmiler]

Maybe in batched HE schemes. In https://github.com/tfhe/tfhe the ratio is much smaller, 2.5kB per plaintext bit.