There are advantages for soft deletes for CRUD architecture, but are there any for CQRS/ES (Event Sourcing)?
I guess if your read model is based on RDBMS then it makes sense, otherwise it depends on the database system in question (i.e. some NoSQL databases like C*[1] and Riak[2] are implementing deletes by writing special tombstone values, which is kind of soft-delete but on the implementation level - but you can't easily restore the data like in case of RDBMS).