Meteor - Why not just publish all the collection data?

This may be quite an easy question to answer as it may just be my lack of understanding, but if you are having to run the query twice - once of the server and once on the client - why not just publish all the collection data, and then just run one query on the client?

Obviously I don't mean doing this for the users collection, but if you have a blog Posts collection, wouldn't this be beneficial?

Publish all the post data, then subscribe to it and running whatever query is necessary on the client to get the data you need.

Publishing everything is good for 'development' environment as meteor adds autopublish by default but this has some fallacies in 'production' environment. I find this two points to be of importance

1. Security : The idea is, supply only as much data to the client as required. You can never trust the client and you don't know what the client may use the data for. For your use case, of simple blog posts, this may not be a serious risk but may be a critical risk for e commerce application. The last thing, you want is a hacker to use the data and leverage a bug in your code to do nasty stuff.
2. Data Overheads: For subscriptions, generally waitOn is used. Thus, till all the data has been made available to the client, the templates are not rendered. IF you have a very large amount of data it will take considerable time to render. So, it is advised to keep the data at 'only what to need' stage to optimize this time too.