Don't use React imports like this. Use Wrapper Pattern instead

This has nothing to do with wrapper files or components, its just comparing importing everything from a library with importing only what you really need.
E.g. you compare

import _ from 'lodash'

with

import debounce from 'lodash/debounce';
import throttle from 'lodash/throttle'; 

but wrongfully suggest that you need a new file to benefit from bundling - you don't. Just don't import the whole library when you need two functions.

what is the use of wrapper here, when you are changing completely what you are importing from the library.

However, if this import is used across multiple component files, the bundle size can quickly grow up to around 40% or even more for smaller projects (~2mb)

I don't think that's how modern bundling work.
For your problem the wrapper is just redundant. The article is misleading, trying to state that by putting something in another file you can "optimize" something.
Also I couldn't find it being used in the repo you, can you point to the exact file?

It's a bundler issue. Not worth for changing.

I also think that this article is misleading as it let the reader think that the suggested wrapper pattern is the actual solution to fix the presented issue.
Like @thraizz says in his comment, no need for the wrapper to fix the issue. The real fix is to load only the necessary modules, assuming the library export them independentely.

Plus, grouping several unique modules into 1 unique "wrapper" file like the given example for Lodash, though in some cases could be a good idea (like to be able to replace any third party tool by an equivalent one), could load to creating "barrel files" which may lead to loading superfluous modules when used in combination with code splitting.