Actually its not because most of the stores which has thousands of product images hire an operator just for digital assets and Smart Bulk Image Upload app makes it in a bulk way to reduce the operational cost 
Here you can find a customer review who directly adressed your hesitation:
“Love this App. 10 Stars. It is very easy to use. Allowing me to import hundreds of images with the SKU and override older images. Lets me know if there are items not found. It is truly a game changer. I don’t think I could handle updates as quickly as we do if we manually updated the images. Oh and the images are stored in your store not on an FTP that you have to pay for space. So the app pays for itself if you have many images. Thank you CS Smart.”
And another one:
"
Extraordinary app that does exactly and without fail what it promises: Avoid headaches when it comes to uploading more than 15K images.
Ozkan’s help is well worth that price, especially to solve the problems that arose when uploading files from my Dropbox that had hundreds of thousands of files. They immediately found a way to do it in a fluid way."
Just give it a try and I believe you are going to love Smart Bulk Image Upload app as well