It's also just easier. When I needed a service for my car (and I didn't already have an established shop where to take it), I just wrote what I was looking for once and emailed the same thing to multiple different places at once.
If I had to call four different places and spend five minutes on the phone with each shop, that'd eat up my entire lunch time.
If I had to call four different places and spend five minutes on the phone with each shop, that'd eat up my entire lunch time.