When water splashes outside the shower.

duh smart ass

A ceiling to floor shower curtain is rare to find...mainly because it is very hard to hang...unless the ceiling is only 7'. Have you already hung the ceiling-floor curtain...or are you looking to do this in the future. Your question includes both present and past tense so it is hard to understand what the real question is.

Are you asking "when" to use the extra long curtains? Under what circumstances would you go that route? The extra long curtains are for low-curb showers (not tubs) or curbless showers (shower floor = tiled to the doorway with a small slope in the corner where the shower head sits) that are very popular in Europe.

Clean looking. I like it.

Taking a hot bath, the shower curtain in theory will prevent the water from cooling down as fast

I prefer having glass enclosures (for the way they look and for being the ultimate splash container) but of course,curtains are a cheaper way of addressing the splash problem

No. You need space above curtain for ventilation. Use conventional length curtain or consult with a shower specialist on a rimless glass door.

Wow...that was one heck of a dilemma

People in general are problem solvers. Here's a video of another type of problem https://video.search.yahoo.com/video/play;_ylt=A2KLqIEZxn5UrmoAWTP7w8QF;_ylu=X3oDMTByZWc0dGJtBHNlYwNzcgRzbGsDdmlkBHZ0aWQDBGdwb3MDMQ--?p=apollo+movie&vid=f5230073d658cf201b3223fb436cc88f&l=2%3A34&turl=http%3A%2F%2Fts2.mm.bing.net%2Fth%3Fid%3DVN.608045770383362293%26pid%3D15.1&rurl=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DKtEIMC58sZo&tit=%3Cb%3EApollo+%3C%2Fb%3E13+Official+Trailer+%231+-+Tom+Hanks+%3Cb%3EMovie+%3C%2Fb%3E%281995%29+HD&c=0&sigr=11b7fiek2&sigt=127hkvfqu&age=0&fr2=p%3As%2Cv%3Av%2Cm%3Asa&&tt=b