Well, to match Elon's galactically over-the-top hype of the Tesla BEV Semi Truck, it would indeed have to have at least fully developed Level 4 (if not Level 5) autonomous driving capability, and it would have to have better than, let's say, 800 miles of range. My expectation is that the concept truck which Tesla will be demonstrating will have neither capability.
The fact that Elon has said this tractor will be capable of full autonomy is one of several reasons why I'm sure that what Tesla will be showing this week is not a production-intent prototype, but rather a concept vehicle cum technology demonstrator. Elon can talk about a fully autonomous BEV semi tractor because he knows that production of such a vehicle is at least a couple of years off, and he thinks Tesla can get to reliable Level 4 autonomy by that time. (Personally I think that's overly ambitious, but Elon has a habit of ignoring such limits... and sometimes he has been proven right to do so! How about those SpaceX reusable rockets, hmmm?)
Returning to the subject of Elon's hype: The target market, which is those buying semi tractors for trucking fleets, aren't going to be impressed with that cabbage. They and their bean-counters will be running a cost/benefit analysis to estimate whether or not buying such a BEV semi tractor and (reportedly) renting the battery pack from Tesla, would cost them less money than buying and maintaining a diesel semi tractor.
They will also be looking at how generally useful and flexible the Tesla semi tractor can be. If it has restricted range, or can only achieve improved efficiency by using special trailers, then that's going to sharply reduce demand. Now, that's not to say that there can't be a niche for a Tesla BEV semi tractor with, say, 250 miles of range. As has been pointed out, there are a lot of daily trucking routes no longer than that. But diesel semi tractor are more generally useful because they can be used on short or long routes. For a trucking firm which runs its trucks on both short and long routes, buying a short-ranged tractor makes the fleet less flexible.
For a trucking company which handles nothing but short/medium haul routes, or one which has advantageous dispatching (for instance, if all tractors on short/medium distance routes return to a central location at the end of the day), then buying a BEV semi tractor restricted to short or medium distance routes may make sense.