You seem to be using size as a proxy for speed: how long until I can use this tool? A slow website (e.g. one that loads 1MB BMPs or un-minified JS) makes you wait every time you access it; a large app download only makes you wait the first time you initially download it.

If I'm going to be using an app on a daily basis for an extended period of time, the speed concerns I care about are how long it takes the app to start up once launched, and how long it takes me to accomplish tasks. Over the lifetime of using an app, I'd argue that an extra two or three minutes in the app's initial download is little more than a rounding error.