We drove to Abu Simbel (with Djed) and spent the night there. I am glad that we did for several reasons.
1) I really enjoyed spending the night at the small lodge in Abu Simbel. The unique Nubian architecture and culture was very different from anything else we experienced in Egypt. It felt almost like being in another country. (Okay, we were almost in another country.) We also ate very good and very fresh fish.
2) We got to visit the temples twice -- once on the afternoon of our arrival and again the next morning. The photographer in me especially liked the early morning light on the second visit. Both times we pretty much had the place to ourselves.
3) We weren't under any time pressure for either visit, and we were free to explore as much as we wanted. When you fly in, I think you only have about 30 minutes, maybe an hour, max. If I am not mistaken, there is one flight in and one flight out each day. There is just enough time between landing and departure to enable you to take a quick look at the temples.
4) In an odd way, I kind of enjoyed the road from Abu Simbel to Aswan. I don't think I have ever experienced such a monotonous landscape. My friend who was with me took a video as we were cruising down the road, and it looks like a still photo. There is a roadside stand about half way between Aswan and Abu Simbel. I was very happy to find a Diet Coke there.
Admittedly, I am in the camp that thinks that terrorist attacks could happen anywhere (including in the US and Europe). I try to take reasonable precautions, but I generally don't sweat it too much. If I recall correctly, we had security checkpoints at the beginning and end of the road to Abu Simbel, as was common throughout Egypt.
Edit: Abu Simbel photos, including the overnight lodging, are here: https://mariematthews.smugmug.com/Egypt-and-Istanbul/Abu-Simbel