Despite that and that it was unverified, oppo research, the FBI heavily relied on it in the FISA applications.
Via Daily Caller:
The veracity of the Steele dossier is once again a topic of intense debate following the Justice Department’s release of secret warrants that the FBI used to monitor former Trump campaign adviser Carter Page. The four applications, which were obtained under the Foreign Intelligence Surveillance Act (FISA), show that the bureau relied heavily on the dossier, which was funded by the Clinton campaign and DNC, to obtain the warrants, which accused Page of being a secret Kremlin agent.
But not only do many of the allegations in the dossier remain unverified, there is reason to doubt the credibility of a major source for the 35-page document, including for claims that the Kremlin has blackmail material on President Donald Trump and about Page’s alleged involvement in a collusion conspiracy.