The preamble of the Preliminary Articles of Peace answers your question.
To be inserted in, and to constitute the Treaty of Peace proposed to be concluded, between the Crown of Great Britain, and the said United States; but which Treaty is not to be concluded, untill Terms of a Peace shall be agreed upon, between Great Britain and France; and his Britannic Majesty shall be ready to conclude such Treaty accordingly.
Britain and the US want peace, but Britain is also at war with France. The US doesn't want to sign a separate peace treaty with Britain and leave their ally France hanging. While Britain and France are working things out, the US and Britain spend the time negotiating their eventual peace terms. Then all the warring parties can ratify all their treaties.
The preamble of the Treaty of Paris also addresses this directly and with a lot more verbiage.
And having for this desirable end [perpetual peace and harmony], already laid the foundation of peace and reconciliation, by the provisional articles, signed at Paris, on the thirtieth of November, one thousand seven hundred and eighty-two, by the commissioners empowered on each part, which articles were agreed to be inserted in, and to constitute the treaty of peace proposed to be concluded between the crown of Great-Britain and the said United States, but which treaty was not to be concluded until terms of peace should be agreed upon between Great-Britain and France, and his Britannic Majesty should be ready to conclude such treaty accordingly; and the treaty between Great-Britain and France, having since been concluded, his Britannic Majesty and the United States of America, in order to carry into full effect the provisional articles abovementioned [sic], according to the tenor thereof...
The documents are very similar, but not exactly same. They have very different preambles, and article 2 of the Treaty of Paris has an extra opening line. That's as far as I bothered to check, because it doesn't matter whether they turned out to be slightly different. It was always intended that the Preliminary Articles of Peace were to be inserted into a final peace treaty.