In a direct way, if you nay need to save data on device, do not need Sqlite.
There is no reason to add something to your code that you will not use (see exception).
Let’s take a look at your example.
If you will send all the information to a Web Service and return all the data from it, you will not use Sqlite. Now, your CRUD may or may not have been in vain, it depends on how your system is architected. If you will save the data to the Web Service, you just need to change the way you save a CRUD Sqlite to send data to the Web Service. The way to do this depends very much on the architeur you are using, but it was just one example.
Then I shouldn’t use?
Well, then we skip a bit of your specific case and talk about applications.
Need to use has, however, it is very common to use for connectivity reasons. Not always will the person have access to the Internet, and losing everything that was done (depending on the application) would be a bad experience for the user.
Now, if you want your application to work only when the device has internet, you do not need this data.
Going a little further, even if your application will return all the data from the Web Service, there may be cases where it is more performative and less "costly" for the user to perform a single query on the Web Service and save the return on Sqlite. Imagine the system making a request to the Web Service to each page just to get the name of the logged in user? This would consume internet and would be several requests to the Web Service that could be handled just by saving the data in Sqlite.
Now, as has been said by @Maniero in comment, cannot answer to say for sure whether you will need it or not. Only you know the scope of the project and what it will actually need.
It’s hard to say for sure, without seeing, without understanding your need. But it’s likely that they do, most programmers today do a lot of things they don’t need, most likely because they want to see the house ready, but they don’t understand what it takes to make the house. If you have more information, I can try to answer.
– Maniero