An app may contain no malware,
but may well be programmed to transmit a user's address book,
location,
and any personally identifying information to a pre-determined location.
This is something that a laptop software package would almost certainly not do, and is what typically sets the two apart. The salient point being raised here is that the risk of malware may not necessarily be the issue at stake with a mobile device; the app itself might well be the Trojan or the virus, willingly downloaded by the user because it was free and performs functions the user desires.