How do Instant-On CFLs work?
The CFLs, in general, have an SMPS inside. The input power (either 110&nbsp;V or 230&nbsp;V) is converted to DC by rectifiers and filters. The DC is then switched at higher frequencies (e.g. 15&nbsp;kHz or 40&nbsp;kHz) AC to run the florescent lamp. That is where the trick is.

The HF oscillator secondary would develop a very high voltage if open circuited. The florescent lamp needs a higher voltage to start, but normal operation is at a much lower voltage. On the other hand, the lamp presents almost an open circuit at the start.

When these two are put together, the high open circuit voltage of the HF oscillator secondary triggers the gas discharge. The lamp starts and presents the load to the HF oscillator and the voltage comes down to the normal operating voltage.

The older designs of CFLs could've used either separate HV sections for starting and operation or voltage multipliers. I saw at least one CFL with separate HV secondaries. In these cases, one part of the circuit builds the ionizing voltage to start the lamp, while the other part provides power for normal operation. In such designs, the time required for building ionizing voltage may be noticeable. So, the light output is a little bit delayed behind the mains switching on.

This is the basic principle, as far I understand. There could be variations in the implementations, though.

In conclusion: no - it should not waste energy. The gas is ionized only during the start-up. The energy consumption might spike a little bit during start-up, but it should only be for a few milliseconds, if any.