The differences between a small seller and Cloudtail seller and Wsretail Flipkart seller could be in terms of pricing, trustworthiness, delivery speeds, and ease of return/replacement.
Answering in Dec of 2020, Wsretail has been discontinued on Flipkart.
About Cloudtail –
Since Cloudtail directly deals with Manufactures/brands as well as big or small vendors in bulk their pricing is almost always better compared to other sellers.
Also, as I have observed most products listed by Cloudtail seller are amazon fulfilled means Amazon’s easy returns and replacement policy and customer support can be handy and useful if you receive an undesired product in your order.
When buying from Cloudtail on Amazon above things are present by default which I believe normal/smaller or niche sellers may not be able to provide (not generalizing)
Not sure whether all these things would’ve applied to Ws retail as well.