Hog and Dogs Ranch / Produce

I have a question? Why do most hog farmers push birthing crates on new breeders,I have never understood, we have raised hogs,swine,pigs,piglets for over 20 years never owned one never needed one. However I did by one a few months ago, for $50.00 from a very smart man that upgraded to a newer model,  through his whole barn  He was very surprised with the reason I bought it Not for what it was intended, We took it concreted it to a 6 inch slab if i need to give a shot  of give any unpleasant anything i just move them into it. works great.  But for having babies NO I am in not way a tree huger but as a mother of 7 you would have to kill me to get me to spend my labor hours and the next 2 weeks after in a box. Whats your opinion and why ?