Why is there a fixed size for integer types in C?

Question

C++ / C#

Greetings.
There are several questions:

1) Why do we need such data types as: int8_t, int16_t and so on. As far as I understand, for better portability of the code, because. on different platforms, the bit size of standard types is different. How true is this?

2) I also heard that these types are used in programming microcontrollers. Can they be used in regular scripts to better control virtual memory consumption?

Answer 1

1) True
2) Possible