"will need" also implies certainty. This feature may never be available within the lifetime of the product being sold today, or indeed the lifetime of the customer or the company. This is misleading.
Tesla is making unverifiable claims about the future of a product which is on sale now.
It is a fact of the digital distribution age that traditional marketing doesn't fit the model of products which can change post-purchase. They are certainly not alone in this, with some very famous cases like No Man's Sky launching with less features than advertised or iPhone performance degrading after an iOS update.
However, this is a machine which can kill people, not a computer game missing content. Let's err on the side of caution with the marketing and not allow companies to talk about what their products can't do.
> No: "...and full self-driving capabilities in the future—through software updates designed to improve functionality over time."
"Autopilot" is not the same thing as full self-driving. What don't you understand? Those statements make perfect sense.
> Yes: "All you will need to do is get in and tell your car where to go."
"WILL NEED". What is not clear? "Will" implies future tense.