Nope not at all. If you have the same usage pattern as that of Apple's target demographic, then nope you don't need it. Today Apple's target demographic is teenagers, interested in pop events, pop music, like to snapchat, tweet, take selfies, don't care what is shared with Google, and want to be limited to what Apple deems appropriate, etc. These activities of the common Apple users absolutely do not require using the terminal.
But in years past, Apple had a number of profession tech users that used the platform because it was, hands down, the best linux platform around. One could use the GUI for general things and when you needed more, the command line was right there. I've used it in SAP, SQL-Server, Oracle, etc. development/tech environments. Unfortunately, Apple has customized the underlaying OS and failed to update the core OS components to the extent that Apple's macOS is not easily usable off the shelf anymore.
We can and must install our own tools through MacPorts or Homebrew. Apple is trying to push macOS to be all sandboxed, which will disallow even that. iOS is already sandboxed. I would love to be able to use linux command line tools from an iPad or iPhone for network/database/server troubleshooting, but alas no, Apple deems it inappropriate.
So yes, for your limited use of iOS it works and I'm happy your happy. But a lot of people, obviously less that the pop teenager crowd, are not happy. That does not make us uninformed or wrong.