Now that I have mine sorted and reliable, I will say I have asked myself this question for the entire 5 years of construction time. I think it comes down to desire and patience. If you want it to be a weekend car, it can be. As long as you understand that there are limits based on the layout and size of the car, you can make it what you want. Some build the cars as near to full-on race cars as possible, with no AC, no sound deadening, no creature comforts of any kind. Some work to get it as comfy as possible. Some have sealed the cabin, others have not bothered.
Mine is probably where a lot of cars are: I have enough heat and sound insulation to make the car quite nice to drive on a nice day. I have earplugs but never wear them, it's not really that loud in the car (unless I mat it, and then things do get more intense...). I am not worried about sealing it from weather because the car is enough of a handful in the dry and I don't think I want to drive it in the wet. I am not going to use it for weekends away because my wife is not interested in it, so that ends that. And I am not overly keen putting my kids in it, because it really is like being on a motorcycle: if you get in an accident with another car, it's not going to go well. I am comfortable with that risk for myself, but not my kids (and I am not that unhappy my wife is not a fan...)
If I was sure of the weather, I could take the car on a trip by myself, say to a track event or some gathering of friends, without issues. I have done several trips to and from VIR, which is about 1.5 hours away and it is just fine cruising down the highway.