I said it sounds like one, not that it is one. I don't know enough about the implementation of it to comment intelligently, but logically it seems to me that if you can compute on it, then it's likely to leak the data, or at least some metadata about the data.

The truth of the matter may be something other. Life is not always logical.

> know companies that use it

We can only do a limited set of operations homomorphically. Moreover, it’s more power intensive than conventional computation. In most cases, local computation is the more effective (and secure) solution.