Shared hosting is the most economical alternative to dedicated servers, VPS or cloud hosting, since resources are divided among many, but at the same time it offers us a lower capacity and availability in resources, as well as less security or configuration to our need.
Nowadays shared hosting is more secure becouse of the "isolation" tecnology between one account and others, as well as a wider range of pre-selectable product configuration, thanks to the expansion and development through time.