C is portable between most hardware. Generally a C compiler is made for any new architecture, and already exists for existing architectures.

C is portable between all operating systems (Windows, UNIX, Mac, etc.) and only needs a program to be recompiled to work. This allows anyone on any operating system to learn about the language and not be held back by intricacies of their operating system.

With this said, C's portability these days is not quite what it used to be. Much of said portability relies on the POSIX standard in particular, and as time passes, the compliance of a given system with that standard is becoming less certain; especially in the case of Linux. Most things will still be portable (or at least emulatable) between Windows, Linux, and FreeBSD for example; but you will at times need to make use of platform-specific support libraries and APIs as well.

Learning C forces you to grapple with the low-level workings of your computer (memory management, pointers, etc.) in ways that the other languages abstract away. Without an understanding of these low-level aspects of computer programming you will be limited if you try to develop an application that needs to run in a memory or performance constrained environment.

Other languages like Python can obscure a lot of details, so your foundation may be weaker.

C is the industry standard programming language, moreover, it is the most popular programming language to use. C is the language used for most Windows, UNIX and Mac operating systems.

While higher level languages languages like Java and Python provide possibilities to be "more expressive" per line of code, it's much more convenient to start with "less efficient" (get me right) language, in order to get initial concepts of how things behave at lower level.

Actually C is a good starting point moving to both higher and lower levels of abstraction, the good example here would be learning C before Assembler, as for general use the Assembler quite hard to understand due to low level of its abstraction (like getting the understanding on how loops work in C before trying to implement them on Assembler).

You can easily pivot knowledge learned here and apply it to almost every other language.

C is standardized and it is the goto language when you have to speed things up.

C was designed to be independent of any particular machine architecture, and so with a little care, it is easy to write "portable" programs (see here). By design, C provides constructs that map efficiently to typical machine instructions, and therefore it has found lasting use in applications that had formerly been coded in assembly language like operating systems or small embedded systems.

Sometimes you really need to program directly in assembly. C’s ABI and common compiler extensions make this a piece of cake.

Sometimes you really need to program directly in assembly. C’s ABI and common compiler extensions make this a piece of cake.

Made of a small set of keywords and rules, only your imagination is the limit. Above all, when it comes to 'pro' programming, C is the only one to rely on.

It sets an early bar that if you can't hurdle you might as well do something other than programming and not waste any more of your time.

Writing in C will require you to understand how things are done. C implies using and understanding the fundamentals. Learning a higher-level language after is much easier.

Capability to program in C is greatly appreciated in developers, creates an image of competency, and many programmers will learn it at some point in their careers.

A lot of languages used in the industry have a C-like syntax (C++, Java, Javascript, C#, PHP) and starting with C will help new developers to be familiar with it's syntax and by extensions with the syntax of many popular languages.