I haven't seen an electric impact wrench in years although I'm sure they still make them. Unless they have changed drastically, they are heavy and bulky with limited torque.
There are so many good air impacts of all descriptions economically available these days, I'm not sure why anyone would consider an electric one. If you don't have a compressor, one of the small 110V pancake or contractors compressors would drive a set of air impacts just fine. Where such compressors come up short is for items requiring continuous volumes of air such as paint guns.
If you had one of these compact, inexpensive compressors, you could then collect a complete selection of air tools such as air ratchets, butterfly, 1/2" pistol grip and maybe an air hammer. These are DEFINITELY worthwhile gadgets to have handy.