To answer this question, we have to look at the feline play-hunt sequence.
When cats play, the behaviours they display are similar to hunting behaviours. Therefore, it is believed that when in play, it is actually perceived by the cat, as a hunting opportunity with a chance of food.
During play and hunting, cats follow this sequence:
Locate > Stalk > Chase > Pounce > Kill > Dissect > Eat
When using conventional toys your cat can reach the dissect phase of the sequence, which is healthy for the play/hunt game. If you choose you can then reward with a small amount of food, following the play, to keep engagement and complete the sequence.
When using laser toys cats never reach past the pounce phase. This means you cat can become frustrated with the play and it can leave them feeling negative emotions, when the game stops. This can then lead to aggressive behaviours towards you or other animals in the household, afterwards or later in the day.
Therefore, we recommend laser toys should be used with conventional toys, never alone. You can then end the laser play onto a physical toy, allowing the cat to complete a full play/hunt sequence. Thus, limiting frustration and negative emotions.