Wouldn’t be too much of an issue to add a diode laser - a 5W one would cut 3mm wood & acrylic. Lower power would cut thinner stuff like paper, cardboard, cloth.
For real work with a laser you need a Yag or CO2 or fiber laser and your costs & doability start to get out of reach. One of those is going to require more structure than the Crossfire table (a low power 40W CO2 laser is okay for up to 1/4" plywood but is a liquid cooled glass tube 3 ft long and requires precision alignment mirrors & lenses). The physical properties of a plasma CNC table are incompatible with maintaining mirror alignment and adding a high voltage circuit (25,000 V) doesn’t mix well with a water table 
If you’re really interested in laser cutting and engraving and are open to some tinkering, a Chinese “K40” off eBay would be a good place to start - and drop you deep in the rabbit hole 