Isn't that all ads, then? I mean, as an end user, which is more harmful to you - downloading a bunch of ads and filling your screen with them, or downloading a bunch of ads and not displaying them?

You are going to use more battery and resources actually displaying the ads, not to mention the worse user experience. If I had to pick between the two, I would prefer 'download and don't display' over 'download and display'

For sure, but any extra battery and resource consumption here would be extremely minor compared to a bitcoin miner. Many apps do various forms of push advertising and background reporting which does quite similar things, do you consider that to be malware too? Ultimately the only difference here is that this one abuses Google and their advertisers instead of the user, which seems to be an accepted and common advertising practice. In my opinion at least, it's not significantly different from those behaviors.