I remember back in the day when all installation programs were offline by nature and easy to transport. It was simple to backup, simple to use, and it didn't require a internet connection. Unfortunately, half of the programs I have used feel that it is an easier method. The basic reality is though that this method of installation is completely ass backwards.
There are plenty of programs that go over 100 megabytes in filesize and these programs should not use a online installation. There are people who can only get a 1 megabit per second download (which essentially is 1/8th of a megabyte per second) and they are getting fucked over by this crap. In addition, what about people who want to back their programs up? These servers are subject to having downtime possibly which is why I don't trust them. The biggest issue is that rather than download them to where they would be installed to, they decide to download everything THEN install it in a colossal waste of time. The companies who use these methods need to get their head out of their ass and at least offer a offline installation option.