I think if having the u/s will ease some of your dh's concerns, then you should consider it as beneficial. If you are having a UP, going for an ultrasound doesn't detract from the experience because you are still fully in charge of your care, you are just hiring a technician for the scan. Also, it will help because it will confirm that everything is "good to go" for a straightforward birth.
When I had my ds it was just me, dh and dd. Dh was in charge of dd once things got intense for me. I played with her and nursed her for her nap and stayed with her while she slept, then nursed her again when she woke up. But once I really got into labor, we pulled out the "goody bag" I'd made for her - a new stuffy, a couple of books and some beatrix potter dvd's - and dh sat with her and slowly went through the bag with her while I labored nearby. He did a great job keeping dd off me when I got in different positions and she thought that meant "have fun climbing under and over mommy". I had everything I needed for labor and birth in a big tub and spread out on the bed within arm's reach.
Also, I gave dh a short list of emergency situations where he would need to get me to the hospital (we were in a hotel across the street because I had to get out of the house during labor - living with ILs). I also had someone who would take my dd if we had needed to transfer. So if your dh can handle being the babysitter and in charge of the phone, and you are capable of doing the rest, you're probably good to go. For some people (it sounds like your dh may be this type) having contingency plans in place help them to stop worrying so they can be present in the moment. "Knowing" that everything is normal with the u/s and "knowing" that there are plans in place to deal with an emergency lets them feel in control so they can leave their nervous feelings behind and get into that confident headspace so they can welcome a baby through uc.
Good luck and let us know how everything goes.