Apps that exist primarily to download and install other applications, especially without clearly disclosing that behavior before the user installs them, are treated as a distinct malicious pattern separate from ordinary malware.
Often seen in "optimizer" or "cleaner" utility apps whose actual function, once installed, is silently prompting the install of several unrelated apps rather than doing the advertised cleanup.
"Your app's primary function is to download and install other apps without adequately disclosing this behavior, per the Hostile Downloaders policy under Mobile Unwanted Software."