I have a nearfield listening position almost identical to the one in the picture link you provided. I even have the same chair and footrest! It's an Ikea Poang chair, with matching footrest, by the way. Very cheap and very comfortable.
I notice no difference at all if the footrest is moved.
If your ears have a clear line of sight to the speaker drivers, especially the tweeters, then there is no reason why the footrest should make a difference for the direct sound waves.
For the indirect sound waves, the closest sound reflections come from the floor in front of the speaker. Performance is generally enchanced if these reflected waves are minimized, by a carpet in front of the spekers for example. The soft surface of the footrest can perform the same function. So as long as the thing is not blocking direct waves, the footrest could actually be a helpful room treatment to the extent that it takes away some of the reflected waves that would otherwise come up from the floor.
So go for it.
I notice no difference at all if the footrest is moved.
If your ears have a clear line of sight to the speaker drivers, especially the tweeters, then there is no reason why the footrest should make a difference for the direct sound waves.
For the indirect sound waves, the closest sound reflections come from the floor in front of the speaker. Performance is generally enchanced if these reflected waves are minimized, by a carpet in front of the spekers for example. The soft surface of the footrest can perform the same function. So as long as the thing is not blocking direct waves, the footrest could actually be a helpful room treatment to the extent that it takes away some of the reflected waves that would otherwise come up from the floor.
So go for it.