It's important to note that both PHP and CodeIgniter can be used for a wide range of web development projects, and the choice between the two will depend on the specific needs and goals of the project. In some cases, a pure PHP solution may be more suitable, while in others, the added tools and libraries provided by a framework like CodeIgniter may be more beneficial.

1. PHP Vs
CodeIgniter :
Do They Differ?

2. What Is PHP?
What Is CodeIgniter?
PHP, or Hypertext Preprocessor, is an open-source,
server-side scripting language used for web
development and easily embedded with HTML files.
CodeIgniter is a prominent PHP framework with a
minimal digital footprint. It is preferred by developers
looking for a simple yet rich toolkit to create
full-featured web applications.

3. Pros & Cons Of
PHP
Plenty of Guides and Documentation
Wide Range of Databases
Cheaper Hosting
Flexibility
Enhanced Laod Speed
Scarcity of Dedicated Libraries
Security Issues
Sinking Popularity
Performance
Unfamiliar Syntax

4. Pros & Cons Of
Codeigniter
Smaller Footprint
Modern Separation Concept
Built-In Security
Easy Set up
Extendable and Customizable
Lacks Comprehensive Libraries
Lacks Focus on Code Maintainability
Limited community support
Poor Documentation
Limited Flexibility

5. PHP & CodeIgniter on Various Aspects
Developing Flash features.
Web-based applications and websites.
Data Analytics and presentation.
Graphical interface design-based applications.
Content Management System.
POS (Point of Sales) system
eCommerce web applications
Payroll processing web app
Invoice management system
SaaS-based web applications

6. Brands Using PHP & CodeIgniter

7. Alternatives to CodeIgniter & PHP

8. Finally , What Should You Choose?
PHP is a server-side web framework, and CodeIgniter is based on it. But still, both have their own pros and cons.
So it would be best to go through the options, check out every aspect of their user experiences,
and make a choice carefully.