In a VFR-only aircraft without dual controls, and nobody else in the cockpit, you can certainly fly an instrument approach in VMC without a safety pilot. You cannot use a view-limiting device, and you cannot log it (legally) as an instrument approach for currency, nor log it as instrument time. I do it all the time, just to stay just a little familiar with instrument procedures should it be required if goddess forbid I get into IIMC. Instrument flying skills are the most perishable in aviation, IMO, and have to be practiced regularly if there is any hope of being even remotely proficient. On every flight I try to practice instrument skills by flying precisely, using the instruments, and I fly instrument approaches (almost all GPS, because there is no other nav equipment installed), but I never, ever, log any instrument time in those conditions. Practice is fine, even essential, but don't kid yourself, it's not the same thing as actual instrument flying, and you can't legally log it as such, and it certainly doesn't meet the requirements for instrument currency, per the FAA. However, and this is a big however, it probably does meet the requirements for CAMTS, and may satisfy them. For those in other areas, CAMTS is a money-generating organization which certifies EMS programs. Their requirements are obviously set by non-aviation personnel who probably have never been in a helicopter, but being CAMTS certified is a big deal to some companies, and is close to being a requirement. Satisfying CAMTS is a priority for some companies, and if flying instrument approaches in VMC helps, then I see no reason not to, and since it's a good thing anyway, why not? Just remember, it does nothing to satisfy FAA requirements in any way. In a VFR program, I don't need to meet any IFR IFR requirements anyway, so it's all moot for that.
@shytorque, the rules in question apply to any pilot, in any aircraft. If you use a view-limiting device, you must have a safety pilot. It matters not if you're a student or an ATP.