You are buying a pro-grade full-frame mirrorless camera body to shoot for the next decade, so you want a tool that handles low light and fast action without needing an upgrade next year. When camera brands roll out new flagship bodies every few years, the previous generation often drops in price while retaining ninety percent of the capability.
Timing your purchase for November Black Friday sales means you can catch retailers bundling lenses or discounting the body straight from the manufacturer. If you buy the right model now, you are investing in a system that keeps up with your work for a long time.
The 0% for 18 months intro window is a strict deadline, not free money; if any of that $2400 balance is still sitting there when the 18 months end, you will get hit with interest on the whole original amount.