Teletype 33 vs. IBM Selectric Terminal 2741 840
The ASR (Automatic Send Receive) 33 had a paper tape reader-punch. The KSR (Keyboard Send Receive) 33 didn't. See was by far the more popular model so it was (and still is, I'd guess) quite common to use "33" to by default mean the ASR version.
I also used both. I liked the keyboard on the Selectric better, and the output, especially with a film ribbon, was so much nicer. I seem to recall that they both got standard maintenence at about the same frequency. At least it sure seemed that the week after the Teletype guy was in to adjust and lubricate the ASR, the IBM guy came in to do the same on the Selectric. If the Selectric printed faster, it wasn't enough that I ever noticed it. I dont' suppose you would so much in interactive sessions, and any time I had them list something I went away to do something else while they did so, so I probably wouldn't have noticed then either.
Sort of mechano-electrical, but I know what you mean.
Lies, Damned Lies, and Statistics 841
Do they give a reason? Unless it requires specialized software from them, and that only works...
Yes. That thing gave me wrist ache after a half hour or so. The teletype I could use for hours with no issues.
As far as I've read and seen, the ones with the phone installed were much less common that the versions without them. Of the dozen or so ASRs and the couple of KSRs I used, I only recall one having the phone setup in it.