I submit images and videos to Adobe Stock and the keyword ranking there is important. The most significant keywords that apply to the image have to go first. With Lightroom you can copy the keyword and the paste at the beginning. This is a very slow process. You have the commas in the way, the panel is small, etc.
There is a software (Stock submitter) specialized for sending content to many agencies and it has solved this with a clever trick. Every keyword or multiple keywords if they are separated with commas are transformed into blocks. You can quickly drag any block into the position you want. No need to care about commas, pasting in the wrong spot etc. It is 100x times faster as it is implemented in Lightroom now. hope to see it one day in LR