A laminate veneer is a thin porcelain layer bonded to the front surface and needs very little preparation. A zirconia crown wraps the whole tooth and is chosen for fractures, root-treated teeth or heavy staining.
Both can look natural. The difference is how much tooth tissue is kept and where strength is needed.
After a digital scan, the dentist plans which teeth can take a veneer and which need a crown. Mixed smile designs can use both in the same mouth.