Its hard to describe, but just seeing a woman in a bikini for me was always just "Ok, you're sexy. I guess?" Meanwhile, looks along these lines to be significantly more appealing and sexy than just letting it all hang out.

It's called not thinking solely with your baser instincts. The woman you linked in the image has character -- she's wearing something that aligns with what she does or is interested in, so it's more than just skin in a barely-there bikini.

Her appearance is designed to tell a story about her character, and if you're attracted to that aspect (or multiple aspects) of that character, it reflects on what you would prefer when wanting to be around someone like that, or traits you might like from a potential companion, as opposed to just a wench in a bikini who is indicating that she's sexy and wants to be oogled, and the men who want to oogle her and wank one off with zero further thought on her value beyond that.