Not necessarily. Cyberdecks and RCCs are able to go hot sim by default, but commlinks need an illegal modification to their sim module to allow it.
Whenever you go VR, you can choose cold sim or hot sim (if able). For routine stuff that people do all the time, (i.e. no opposed tests) like visiting a virtual bar or conference room or visiting a virtual furniture store, cold sim will be more than sufficient. For shadowrunners that are likely to be subverting normal security protocols (opposed tests) the +2 dice pool bonus is invaluable and worth the risk in my opinion. So generally, Deckers will default to hot sim because even matrix perception and matrix search get those 2 extra dice. But nobody has to go hot sim if they don't want to.
Given the 3D6 initiative that comes with cold sim, you have a pretty good chance of getting into the 20s on initiative and therefore getting 3 actions in that combat turn. If you go hot sim, your initiative dice are 4D6 and you're almost certain to get past the 20s on your initiative and depending on how high your Intuition + Data Processing gets, you may have a reasonable chance to score 31+ giving you 4 actions per combat turn.
The risks come in 2 areas: First, IC and deckers that are using biofeedback attacks will do damage to your meat body in addition to your deck. That biofeedback damage is physical if you're in hot sim, or stun if you're cold sim. Plus any time your deck gets bricked you take 6 biofeedback damage (resisted with Willpower only since your deck is dead). If you were hotsim when you got dumped, the biofeedback damage is again physical or stun if you were cold sim. You never suffer biofeedback damage when in AR.