Is EC integrated encryption scheme used in practice?
Yes, ECIES is used in practice. That's the simplest way (thus arguably the best) to establish a key or/and encipher using Elliptic Curve Cryptography in contexts including unidirectional data transfer, or data-at-rest like backup with encryption under public key.

As an illustration, it is often listed in the Other algorithms section of FIPS-140-validated cryptographic devices; I count like 28 occurrences.

ECIES is in the de-facto standard SEC&nbsp;1, IEEE&nbsp;Std&nbsp;1363a-2004, and ANSI&nbsp;X9.63-2011. It is used e.g. in Intelligent Transport Systems as specified by ETSI&nbsp;TS&nbsp;103&nbsp;097. The similar ECIES-KEM is in ISO/IEC&nbsp;18033-2:2006 following a well-documented proposal by Victor Shoup.