If Scotland and England were one country, then Scottish merchants would gain access to English colonies, markets, raw materials and financial advantages. This would mean that Scots had level competition with European rivals for trade. Union with England might help Scotland recover from the failure of the Darien Scheme.
In addition, the stability created by Union would lead landowners and farmers to invest in land improvements. A reduction in poverty in Scotland was also more likely under union.
If the wealth and living standards of people could be increased, then there would be less civil disturbances.
As part of Great Britain, Scotland and England would speak as one country, giving Scots greater standing in Europe.
Scottish representatives would be at the King’s Court in London, and therefore, English interests would not dominate when the King was receiving advice.
Anti-Jacobites supported union as it would mean that the Hanoverian succession would be secured. Following the death of Anne's last surviving child (Queen Anne succeeded King William to the Crowns of England and Scotland), an English Act of Settlement of 1701 settled the succession on Sophie of Hanover and her Protestant heirs. Sophie was a granddaughter of James VI of Scotland and I of England, and Queen Anne's closest Protestant relative.
Scotland would have greater security with union. England was the most powerful country in Europe. Any chance of an invasion of Scotland by foreign powers would be reduced. This would benefit England also, as the threat of invasion of England by both Scotland and France would be lifted.
Despite wanting to remain independent, some Scots accepted that union would be a logical step. There was a common cultural interest between Scotland and England, with a shared history of language, religion and trade.
The Presbyterian Church would remain. For Protestants, the threat of pro-Catholic interests would be removed with Union, since the English Act of Settlement prevented future monarchs from being Catholic.