This is something I don't understand. Raven, who is very sensitive to noises and scares easily, will sit and watch the vacuum cleaner. Neither the bulkiness nor the noise seem to bother her and I can vacuum within about 4 feet of her before she gets up and moves away. This is a kitty who can be startled the the sound of the refrigerator door opening!
That's one of the wonderful things about living with pets. There's always something they do that will amaze, amuse, or confound you.