Veneers aren’t the same as dental implants or crowns. Veneers cover only the front surface of the tooth, while crowns encase the entire tooth. Veneers are also thinner than crowns: about 1 mm, compared to 2 mm.
Veneers are less invasive, too. If you need a crown, your dentist will have to file or ground down more of your tooth to prepare it for the crown than would be necessary for the application of a veneer.
Meanwhile, an implant is installed in the bone to replace a missing tooth, and a crown is placed on top of that. It can take several months after the implant is placed for the area around it to heal enough for the replacement tooth to be placed on top.