As a rule, I'm not a solitaire player. I'm not even that into playing against AIs. However, over the years, I have ended up playing a number of solitaire games. And, like I said, most of them have been ones I've made in the name of print-and-play.
Looking back, I'm pretty sure the first one I made and played was Malta Convoy. And by made, I mean printed and and got out some dice. The game simulates the WW II American convoy to deliver supplies to Malta. However, you really just roll the dice to see what happens. It tells a story but it doesn't really offer much in the way of choices. It's biggest virtue is that you just need to print one page.
Of course, there are a lot of solitaire games out there that fit that criteria now.
The solitaire Print-and-Play I've gotten the most play out of, beating out even Onirim, is easily Zombie In My Pocket. Tile laying, resource and time management, and a very strong theme. It is a fun little game.
A solitaire card or board game is a combination of puzzle solving, imagination and wool gathering. It's a mixture of meditation and killing time. The process of actually making it just adds to both of those aspects.
I'll freely admit that I tend to make ones with minimal components. And certainly not all of them are winners. Sometimes, they're just interesting ideas to look at, even if they weren't actually interesting to play.
However, crafting a solitaire game adds to the entire experience. It is a game that you play on your own. Making it yourself brings the experience full circle, making it self-contained and entirely your own.