Favorable Google ranking
Websites running on .ca domain receive favorable Google ranking within Canada.
A business may therefore rank higher on search results within Canada. Higher ranking will likely lead to more sales within Canada for the particular business.
Credibility within Canada
Businesses running websites with .ca receive better visibility and credibility in Canada compared to websites using other Top Level Domains.
Demerits of using .ca domain name
.ca is a restricted domain. Canadian Internet Registration Authority (CIRA) require proof of residence within Canada.
Therefore you have to have a Canadian residency to use .ca domain name.
.ca is a country code Top Level Domain meaning its traffic is likely to be localized by Google and therefore the business brand will likely serve Canada only.