Not really that much. Remember, the Commlink can only provide the Data Processing/Firewall, and maxes out at 3/1, so it's not that secure. You can go with Cyberhacks (H&S, p. 33), that go up to 3/6, but without a Cyberdeck, you won't have any Attack/Sleaze attributes, making you unable to defend yourself and easy to find. Your device also determines your Matrix Condition Monitor. You can also not use hot-sim VR without jacking in, so you lose that in initiative.
Basically, no cyberjack/cyberdeck/cyberhack means you can attempt the actions, but you're pretty defenseless if coming across other deckers or IC. Also, you do still need to invest in the Cracking and Electronics skills to do most of the Matrix actions.
But yeah, Matrix Searches, Jamming Signals, Controlling Devices, you can still do all that, just not as well as a decker.