First it is very important for a beginner to learn all the techniques. But why not sparring right at the beginning? Of course it is the free decision of every beginning student to take part of Muay Thai sparring or not.
I can only bring my experience into this thread.
I was the co-head coach in a big Muay Thai Gym in Germany before and responsible for the beginners. We let them spar also but it was very different to the advanced students (fighters included). One of the Gym goals was to bring out good fighters. But we had very different motivated students there, so sparring was only a must for the fighters class.
It is the coaches responsibility to observe and control them very carefully and to put more sensibility into the students, which isnīt that easy. Beginners cannot control their power or their techniques like advanced students, so the risk of insuries is very high.
During the sparring we stopped the training after every mistake or wrong technies the students made to explain them what went wrong. And of course we watched very carefully that the sparring isnīt goin to be very tough and to hard.
In the case of protection. Everybody had to wear Shin Protectors and of course the normal Muay Thai Equipment. To wear Head Protectors was also needed, but just for the beginners.
Sparring should be a part of the whole training session in Muay Thai both for beginners and advanced students.
Just my 2 cents.
Best regards
Guido