That's a good question. Honestly it works OK when doing the quick heat method, it's not bad at all, it's just not as good as it could be.
Part of the magic of the E-Nano in my opinion is how consistent and dependable it is. Once it's heat soaked, it's very hard for one person to drop the heat on it, if not impossible. Perhaps in a group setting you could overpower the heater.
Also, it always gives me the exact same results every time when it's heat soaked. Same flavor and clouds every time at my preferred setting on the temp dial.
When using the quick heat method I find I have to bump the temp up .25-.5 to get similar performance. It varies so I'm not always in my preferred "sweet spot" as far as results. It gets the job done for sure, but it's not as pleasurable to use.
Also, it is possible to overpower the heater at this stage, so you may get a good hit followed by a thin and wispy hit. The consistency is not there until the nano is heat soaked. You can work around this by taking a short break between hits.
In short, there's nothing wrong with using the fast heat method, just remember to turn the temp back down lest you combust! It's not like you will waste material or anything, and you will still get 90% performance.
For the true log enthusiast, only 100% performance is acceptable. That's why you see people recommend a full heat soak. We have high standards around here!