The primary advantage of gas plants is much faster ramping of output than others - they are energy-inefficient by comparison, but they are meant to handle spikes in demand in the grid. All of them will be of hot start (<8h) as even the steam ones use relatively small boilers that are quick to get up to speed, compared to conventional power plants. As result, they are kept on stand-by or operating at very low output except for when the spike needs to be handled.
You can definitely use the longer times found with CCGT when describing ST power plants - although even longer times will be found (gas burners and big boilers are cheaper to build than gas turbines; the CCGT will usually be smaller than ST plant).
I'd be more concerned over the inflated numbers for CCGT; they reach ~40-60% of capacity in time typical to GT plants, and then ramp up the output to 100% over the time typical for ST. That's also why you find the wildly varying values for the gradient in the document - not only is there the slow climb of steam part trailing a long way after the gas part, the power output of the gas turbine depend strongly (and non-linearly) on RPM (which again climbs at rate dependent on that power output) - generally, first 30% or so will be rather slow, then the engine picks up and the 50%-80% ramp is really steep. Regardless, 5-10 minutes is an adequate estimate of the time from ignition to full power (not sure what preparations the operator must perform beforehand). And then water in the steam part only starts heating slowly, steam turbine a long way from budging...
Any kinds of averages or momentary measurements in CCGT are seriously misguiding due to that awfully non-linear output ramp.
Similarly, for GT, the 100% output time and climb rate will depend strongly on each other. If you allow the GT to spin up with coils off, all its power directed towards increasing RPM, it will reach peak torque RPM quickly, and provide 100% output in a really short time since. OTOH if you ramp it up while drawing power, the extra load will reduce climb rate of RPM and delay reaching 100% output. So, a choice between 5 minutes of nothing, then 100%, or 12 minutes of output that is maybe 20% over the first 7 minutes, and then climbs to 100% over the remainder of the time.