Advantages and disadvantages of exclusive images uploaded to stock photo sites. Is it worth selling your photos in just one place at all?

The concept of exclusivity in stock photography
If you mark a photo as exclusive on a stock photo website, you are allowed to sell that image on that page only.
If you are an exclusive stock photographer at an agency, you can only upload all your photos there for sale.
There are agencies where you can choose whether or not to upload your photos as exclusive (such as Alamy, Dreamstime), and there are places where you have no choice because all your uploaded images can only be exclusive (such as Stocksy).
It is important to know that exclusivity does not cover non-commercial appearances (e.g. you can post images on social media), sales on POD sites (print on demand companies), or you can use and sell your exclusive images on your own website.
What’s the benefit of having a photo available at only one stock agency?
If you photographed in special places, special events, special compositions, and it is likely that the images will be in demand, it is advisable to upload them to a site where the photos will sell for more money (Alamy, Getty Images, EyeEm). By setting the images to exclusive, your customers can be sure to get unique photos for their money.
The above case is probably rare because a subject that is in demand is usually well-photographed.
Exclusivity can definitely work for a well-known stock photo company with many clients.
Of course, there are also monetary and other benefits to exclusivity. You can find more information on each agency's own website. They usually give you a larger share of the price of each sale or put your images higher in the search result page.
What’s the benefit of uploading the same photo to multiple stock photo sites?
Many stock photographers choose to upload the same portfolio to multiple agencies. They do this because they earn some money from each of the sites: 'many a little makes a mickle'.
Experiences and opinions are different about whether it is worthwhile to post the same images both on cheap microstock (e.g. Shutterstock) and more expensive midstock / macrostock (e.g. Alamy, Getty Images) sites.
My own experience: I noticed quite a few times that a buyer on Alamy searched for a subject, viewed at one of my pictures, and then bought the same photo on Shutterstock for some 10 cents that day. This happened several times.
Some people think the audience of each agency is different, and many buyers don’t look around elsewhere before paying the higher amount. In fact, some companies subscribe to or contract with one stock photo agency and only purchase pictures from there. I also know private people who stick to one stock photo brand.
I, at the suggestion of several stock photographers, shared my portfolio and uploaded different images to micro- and macrostock sites. Then later I only selected one company, so I became absolutely exclusive.
Disadvantage of exclusivity
In addition to its many advantages, exclusivity can also be a disadvantage. It’s hard to guess which of your images will be successful on which site, where there will be more interest in them. If you mark an image as exclusive, you will never know if you generate much more revenue on another site.
The basic rule of stock photography is that you should only upload your best images, so by no means expect more sales from exclusivity if otherwise your portfolio is not unique.
Personally, I don’t recommend being an exclusive photographer, meaning you only upload your photos to a single agency. Should you run into a much better stock company at any time, it won’t be easy to get rid of your exclusive agency.
Summary
After a few years of trial and error, I chose Alamy as the only place where my stock photos are available. All my pictures are exclusive, but I’m not an exclusive photographer with them.
According to Alamy’s policy, exclusive images are automatically investigated for unauthorized use, which may even be an advantage for me.