Good question. Usually because there are not enough teachers in a school, or even a school district. Some people enjoy teaching children. There are many answers for that question, I hope that I helped, you may take my answers, or continue thinking of reasons why.
No, there is no need for 'substitute teacher' to be capitalized.
Yes, both "Substitute Teacher" and "Substitute Paraprofessional" should be capitalized when referring to specific roles or job titles.
Substitute teacher.
You should respect you substitute teacher because they are just like a normal teacher and deserve to feel as if they were. Treat them the way you would want to be treated if you were in the same position!
She works as a substitute teacher.
The substitute teacher is Firenze, a centaur from the Forbidden Forest.
Takes the place of a regular teacher that is absent that day.
No
Lisa's teacher is Miss Hoover (Elizabeth). She was replaced for the episode 'Lisa's Substitute' by substitute teacher, Mr Bergstrom. her specific jazz teacher was Bleeding Gums Murphy
Substitute could be an adjective or a noun. For example, "The substitute teacher" uses subtitute to describe what kind of teacher. "The substitute passed out the homework" uses substitute as a noun by itself
In Australia, at least, to be a substitute teacher, you still need all the qualifications necessary to gain registration as a teacher. You cannot teach without a degree or the equivalent teachers course accreditation. This applies whether you are a full-time teacher or a substitute.
In most states, to be a substitute teacher in the public school system takes the completion of 60 college credits. You should check with the Board of Education in the area you would like to teach for detailed information.