How so? The phone is largely someone else's device and as such not as trusted as your own PC.

Also, phone taps record what you say in one particular case versus PC trojans which could record everything you do or say near the computer, and everything you do on it. Trojans also put your whole computer under the attackers control and makes can make it appear, forensically, that you were doing things. If they download porn, it appears that you downloaded porn. If they send spam, it appears that you sent spam...

If sinister means dangerous, then I think trojans win hands down.