Fatty acyl-coenzyme A (CoA) diphosphatase that hydrolyzes fatty acyl-CoA to yield acyl-4'-phosphopantetheine and adenosine 3',5'- bisphosphate (By similarity) (PubMed:32915949). Preferentially hydrolyzes unsaturated long-chain acyl-CoA substrates such as oleoyl- CoA/(9Z)-octadecenoyl-CoA and arachidonoyl-CoA/(5Z,8Z,11Z,14Z)- eicosatetraenoyl-CoA in the endoplasmic reticulum (ER) lumen (By similarity) (PubMed:32915949). This catalytic activity is required for maintaining ER structure and for lipid droplets (LDs) biogenesis, which are lipid storage organelles involved in maintaining lipid and energy homeostasis (By similarity) (PubMed:18160536, PubMed:32915949). Directly binds to diacylglycerol (DAGs) and triacylglycerol, which is also important for LD biogenesis (By similarity). May support directional budding of nacent LDs from the ER into the cytosol by reducing DAG levels at sites of LD formation (By similarity). Plays a role in the regulation of cell morphology and cytoskeletal organization (PubMed:21834987). {ECO:0000255|HAMAP-Rule:MF_03230, ECO:0000269|PubMed:18160536, ECO:0000269|PubMed:21834987, ECO:0000269|PubMed:32915949}. This is the function of Ensembl gene identifier ENSG00000197296 (FITM2, fat storage inducing transmembrane protein 2).