You are buying this setup so you can pull great shots at home for the next decade, which means we want to get the machine and grinder right the first time. A good setup keeps you out of the coffee shop line and pays for itself over a few years, as long as you actually use it.
Wait to buy until the brands drop their new models. That is when retailers mark down last year's top-tier bundles to clear shelf space, and you get the exact same build quality for a lot less cash.
Just remember that the intro window is a hard deadline, not free money. If you still have a balance left when those 18 months are up, the standard interest rate kicks in on the whole original amount, which ruins the discount you waited for.