If you are new to the field of design, don’t think that you’ll be able to create without copying from existing creators. Actually one of the first things for anyone new to the field is to follow someone already in the field and try and replicate their designs. Surprisingly, there’s a positive side effect of copying: conventionality. Building on the same foundation as other sites — specifically, layout and information architecture — often leads to intuitiveness and familiarity for the end-user. In simple terms you have something that the users are already comfortable in using, this will require lesser user research and save time as well. The reason that so many companies are adopting this style is that it helps them in focussing on other aspects of their platforms, and also helps them in saving money used in designing. By no mistake do BarnesAndNoble.com and Amazon.com have similar navigation structures!
The main reason for this is that there are so many apps and websites these days that people are just done with new ideas. But developers are increasing day by day so what should they do? They try to create better versions of existing things in the market. This way the ideation phase just gets deleted and the just have to make the platform better faster and more reliable. And this is why you can find replication of so many applications and websites these days. Just make existing stuff better and you have a chance to a 100M downloads or users.
Given the time constraints and budget limitations that designers face, copying is almost mandatory. But this doesn’t stop you from being creative. There are two types of copying, one is blunt wherein you try to literally make an indistinguishable clone, and the second one being smart copying where you try to replicate all the essential details but change physical parameters like color, size, etc to make it look like it’s something new, not only this but you try to introduce certain new functionalities as well which gives the website or app an advantage over its competitors.
This is what happened with JioMeet as well. They saved hours in making a new design by copying Zoom’s UI. They copied almost everything but with a different shade of color, as you can see in the screenshot below. If you notice they even added a help section in the bottom navigation which gives an added usability to the user if he has any questions regarding the app.