Swan Safety Fountpen Ink Window

Although I recently shared an ad about the Swan Safety Fountpens (and the delightful pricing), I came across another Swan Safety Fountpen ad that I enjoyed. The ad below emphasizes the features of the pens: they never leak because of the screwdown cap, they never blot because of the ladder feed which controls ink flow and supply, and they always write because of the feed and 14KT gold, iridium-tipped nib. Aside from that, the "little windows" are viewer ports in the barrel which allow the user to see the ink level inside. I appreciate this feature as in these solid barrels, ink levels are otherwise impossible to determine until the pen runs dry. As compared with vintage pens, modern pens more commonly have ink windows (or are completely clear), which makes it much easier to gauge ink levels. Is this a feature you appreciate in a pen?