I think, storing mobile phone apps in PC is an old concept. These days, almost everything is on the NET, and that will be future as well. Just use Google account will keep track of the list of apps you installed, so really no point to keep them in PC or on a 3rd device.
Since a full wipe or flash the phone with new ROM may needs to reinstall all the apps. Having it keep track by a remote server is more convenient than storing it into the PC. I had performed ROM upgrade while I was travelling in train. Once I reach office, my phone was upgraded with the latest ROM.
Just curious, if the PC/Mac dies, does it mean you lost everything or simply just download everything again once you use a new system? If it will download for you again, then there is really no different. Apple just added another intermediate apps for your iPhone to sync, which quite frankly, pointless. Why is there a need of this "middleman"?
These days, even my phone contacts are sync to my Google's account. Changing Android phones and retaining my previous setting is quite effortless (You can choose to save them, and manually transfer, if you prefer).
Not to mention about freedom after rooting... Once you tasted the joy freedom, you really don't feel like going to jail...
