It's just a brand name that have become a style over time, no different to zoggs or funky trunks but those names don't have the same panache. Speedos were what Australian life savers wore at the beach, their swim team adopted them and it's gone from there. I wear swim briefs all the time for lap swimming, they are the next best thing to being naked when you can't be. Light and minimal and not hiding much.
It's just a brand name that have become a style over time, no different to zoggs or funky trunks but those names don't have the same panache. Speedos were what Australian life savers wore at the beach, their swim team adopted them and it's gone from there. I wear swim briefs all the time for lap swimming, they are the next best thing to being naked when you can't be. Light and minimal and not hiding much.
Do you have any Cooltan briefs?
Speedo started selling swimsuits when attitudes were way more conservative than today, and bathing costumes were likely to be made of wool. In comparison they were sleek and brief. (Not too brief, Bondi's swimsuit inspectors may order you off the beach!) I think the original ones were a trunk style while 3" sides were common when I was a kid.
The Cool-Tan and other tan-through fabrics certainly feel more open than conventional fabrics, but nowhere near nude or even fishnet in the breeze or the water.
The big advantage is their quick drying which again is somewhere between nude & conventional fabrics. Tanning is also at some midpoint, so I don't expect to make great progress in that department beneath the fabric. Perhaps if I wore them for longer I'd get three levels of tan: exposed skin, under the fabric and under the elastic. That said, I now generally wear Skinz loose shorts in a mesh fabric on my way to the CO part of the beach and move the band up and down a little periodically.
The visual opaqueness does vary with the pattern. Areolae, nipples and butt cracks may be noticeable on close inspection depending on where the fabric pattern falls. Not sure about the penis as I cannot see myself from the correct angle.
One nice side effect is when emerging from the water in the sunlight, for a moment each of those tiny holes holds water for a spectacular glistening contoured sight. Works best on a one piece of an obliging female.
Finally, the fabric is delicate and is not likely to last as long as other fabrics.