Well i think it demonstrates more a lack of knowledge/technique/skill, this is clearly shown by the way he's constructed the model in the first place and by principle i mean by way of doing it properly, as everfresh pointed out fastest way is better, as long as it doesn't compromise quality, and if this was a commercial piece and under deadlines then fair enough, make it with drawn splines and extrudes, as it would be faster, if it's seen from a distance, yea even better i wouldn't even bother bevelling the edges, you could make an argument for that in a commercial environment, or it was a quick concept model to realise an idea have ngons and triangles all day long, as that is not the final model, and a fully quad based higher poly model will be created later on based on the original concept.
But when you're trying to make a profit from a model, that's in competition from other models that are either equal or of better quality, which he specifically stated as wanting the model to attain a level of detail surpassing the other models on the website then you're not gonna have the flexibility to achieve that with just extruded splines, i agree trying to make it quads afterwards is not the way to go, if that's the aim do that from the beginning, but using boole's the results are inconsistent and create equally horrendous topology. As cerbera pointed out many websites ngons are a strict no, as in they will not accept the model if it contains them, triangles not so much. really it all comes to down to personal preference, i've seen litterature sold and bought and distributed in the thousands by places like cgsociety that contain absolutely horrendous examples of topology, modelling and just over all laziness that would make Cerbera wet his big girl knickers! and that is from some renowned industry artists and these are being sold for like 60 -170 dollars and are currently sold out images below are from
these books
http://www.ballisticpublishing.com/books/dartiste/character_modeling/
http://www.ballisticpublishing.com/books/essence/face/
https://gyazo.com/7b5b8ff8c311e0333a7488f49159e250
https://gyazo.com/d5e74c449eef1422fbb28e614edfa60e
Now although I've been assured theres is good content in these book's (i don't own them personally) the fact they contain stuff like that is unforgivable imo.
So it would seem a lot of people would agree with you that 100 percent quads are not necessary, nor is getting rid off all the ngons or triangles, but personally to me and Cerbera atleast, just because you don't need to do something to get the job done, doesn't necessarily mean you shouldn't and personally i'd rather be called out for being a quad Wh0re and overly obsessive with meshes, than put my name to anything resembling the examples i posted here.