First of all, I can't answer for pessimizer, but I'll list some potential advantages of using rsync. Second of all, I really need to point out that there's a big difference between convenience and flexibility, so our technical evaluations don't really challenge eachother.
rsync might involve more work, but on the other hand you could have a cron scheduler trigger it at regular intervals, run by a script that only performs a backup under the right network connectivity conditions (eg. the phone is connected to your home or work WLAN). Perhaps you only want to back up part of the system, or maybe you want to back up some parts of it (say, /home) more frequently than others that are susceptible to big changes (/usr/bin?). Perhaps the only thing you really want to back up from your phone are your downloaded email attachements and browser downloads, while having your contacts managed by some cloud service. You've already listed the disadvantages of such a setup, and I agree, but the advantages need to be acknowledged as well. The stream-lined iOS approach might be as one size fits all as it gets, but there could still be cases where a user would reasonably want to handle it differently.
As for what use ssh for, you are being clear now. At first I thought you meant using an ssh client on the phone (in which case the answer would be the generic answer to "what would I use ssh for?"), but running an sshd on your phone could be useful as well. It's a quick and convenient way to move files to it -- think binaries, scripts, crontabs or runit services -- and a quick way of managing these files.
rsync might involve more work, but on the other hand you could have a cron scheduler trigger it at regular intervals, run by a script that only performs a backup under the right network connectivity conditions (eg. the phone is connected to your home or work WLAN). Perhaps you only want to back up part of the system, or maybe you want to back up some parts of it (say, /home) more frequently than others that are susceptible to big changes (/usr/bin?). Perhaps the only thing you really want to back up from your phone are your downloaded email attachements and browser downloads, while having your contacts managed by some cloud service. You've already listed the disadvantages of such a setup, and I agree, but the advantages need to be acknowledged as well. The stream-lined iOS approach might be as one size fits all as it gets, but there could still be cases where a user would reasonably want to handle it differently.
As for what use ssh for, you are being clear now. At first I thought you meant using an ssh client on the phone (in which case the answer would be the generic answer to "what would I use ssh for?"), but running an sshd on your phone could be useful as well. It's a quick and convenient way to move files to it -- think binaries, scripts, crontabs or runit services -- and a quick way of managing these files.