That could be a very useful and popular niche, construction sites without power at early phases of construction aren't rare and power tool batteries are expensive.
For a lot of truck owners, there's going to be some resistance because they love having a v8 engine etc. I don't see those people moving over quickly (although they might be swayed by the acceleration/speed). But if you're using one as a tradesperson, this seems like an absolute no-brainer. You're not driving enormous distances regularly and if you're able to run your entire job site for free, as well as have lower servicing costs... why wouldn't you?
I'm sure gas guzzler enthusiasts will continue to exist, but the financials don't make sense; it would be far cheaper for them to daily drive an EV and keep the old guzzler for fun days. They'd save on gas and maintenance by not driving an ICE all the time, and they still get to use it whenever they have free time.
In conclusion, my argument is that Ford/whoever will still eventually capture these enthusiasts, because they can still keep their old trucks but will always eventually need a new one.
Perhaps.. but we'll have to see how the battery holds up under extremely hot or cold conditions to really know if it will be used that way; and few people will want to be stuck at the job site after the end of the day.
However, even better for that kind of stuff would be a hybrid with a smaller battery, but a generator in the frunk (sort of like the Volt).
Unfortunately I don't think such a vehicle exists yet, while hybrids and even plug-in hybrids are common, they aren't designed to be used as power stations/offer multiple 110v outlets.
This new F-150 is rare in that the manufacturer actually supports its usage like this. If you use a Tesla as a glorified battery they will actually void your warranty.