I don't think that Diana married Charles for "status and perks". She hardly needed status, because she was the daughter of the Earl Spencer. Not only did she have the courtesy title of "Lady Diana", but she had family that was closely connected to the Royal Family on both her father's and mother's sides. She was a wealthy young woman in her own right, from the money that she inherited from her ancestress Frances Ellen Work. If she hadn't married Charles, I'm sure that there were other titled and/or wealthy young men she could have married.
I do believe that she either was in love with Charles or was fond enough of him to be convinced that she was in love with him. The belief that he could never divorce her was, I believe, part of the reason she married him. She wanted to marry for love, and she didn't want to be divorced.
Yep. By the midpoint of their marriage, she probably did feel that the only value (aside from her sons) that she got from it were perks and status, so might as well take advantage. But I seriously doubt that was what she valued at the outset.
I think both Charles and Diana were at vulnerable transitional points in their lives when their courtship began, compounded by the intense press attention, and it lead each of them to overestimate their compatability.
Charles was likely smarting from the kind of attention his string of failed relationships had drawn to that point. The press was turning on him and becoming increasingly catty about what "experience" his girlfriends had with other men. He'd seen so many of his friends marry and settle into the next phase of life that he must have felt as if his clock was ticking. All that could easily combine to put him in the right frame of mind to interpret what should have been slight nudges towards marriage and finding a "virgin bride" as being giant pushes in that direction. What's more, I don't really think he was romantic with Camilla at that point; rather, she was a best friend, which meant that he didn't really see the need to find a wife who filled that best friend role. From his point of view, that probably lowered the bar for what kind of relationship he needed from a potential bride.
Meanwhile, Diana was newly on her own, in that phase when many of us fumble about trying to figure out which of our adolescent likes and habits will fall away and which will remain as part of our adult selves, and I don't think she guessed right. For instance, I suspect that she thought she'd like the "country life" Charles offered because (a) she assumed she'd grow into enjoying the same things the adults in her sphere enjoyed and (b) what she'd known of it to that point had still been a kid version, spent at a house where everyone still looked at her as a vulnerable, sensitive child and thus allowed her to hang onto a child's habits and pastimes (this includes hanging out in the kitchen with staff who approached her with a quasi-parental attitude). Perhaps more importantly, she wasn't very experienced with romance, and what examples of it she'd seen from her parents' love lives and divorce probably served more as a caution for particular things to avoid than a primer in what strengths to look for and value. She wasn't really in the best position yet to be able to tell the difference between admiring a man and falling for him. She'd also probably been coddled more than she realized.
So he was primed at that particular moment in time to look at a young woman like Diana and see the ideal bride who he could come to develop affection for; she was primed to look at an older Charles as a stable presence she could come to love who lived a life she could settle into liking. I do think they liked each other just fine, but they didn't spend enough time another alone to realize the ways their personalities could grate against each other. The press was following them with an intensity that went beyond anything the rest of the royal family had experienced during their own courtships, which backed both Charles and Diana into corners where it would take a great deal of inner strength to admit to themselves, much less others, that their connection might not be strong enough.