It's important to realize that the term "32bit" can mean different things to different people. Context plays a large role.
32 bit color depth is an aspect of photography. Photographers use 16 or 32 bit color depth to store as much possible color data per channel as they can. Doing this allows photos to be adjusted and retouched with much more precision, clarity, and prevents banding or "broken pixels" during the retouching stage.
Think of it like working on a logo in PNG form you snagged from a client's website versus using the vector version of the logo. 32bit color is to photography what vector is to design in that it's desired to achieve the best results possible.
In terms of design, 32bit color depth doesn't really play a large role. In order to reproduce any image it has to be an 8bit color depth image.
Designers aren't accustomed to "32bit" meaning color depth because, as far as I'm aware, nothing reproduces 32bit color depth images. For reproduction, everything needs to be down sampled to 8bit color depth - print or web. So, for designers 24bit often refers to a standard RGB image (8R 8G 8B) and "32bit" often refers to an RGBA image (8R 8G 8B 8A) or an 8bit CMYK image (8C 8M 8Y 8K). But that's not the same as 32bit color. This is where it starts to get confusing. :)
A "designer's" workflow doesn't often utilize 32bit color depth unless they are doing photo correcting and retouching. In which case, the folks over at https://photo.stackexchange.com/ will be able to assist far more with workflow suggestions and questions than many deisgners will be.
All that being posted, as a designer if you are creating raster images, you are absolutely free to create them as 32bit color depth images. As pointed out by @MichaelSchumacher in the comments below, using a higher color depth will assist in smoother gradients or blurs or anything where subtle variations are desired. In the end, you will still have to down sample to 8bit color depth to reproduce, but while creating you may find some advantages to working with higher color depth.