Don't forget that they'll change their API every so often, so you'll spend days and weeks to adapt to "v2" before "v1" is deprecated and eventually removed. You will usually get nothing in terms of desirable features for doing that work, quite often you will get new bugs instead that weren't present with the old API, or even worse, features you depend on are removed because "almost nobody really used them" or "they aren't a good fit in the new interface anymore", and of course you won't have the choice of simply keep using the old version of the thing for an arbitrary amount of time to perform that update on your own pace.