Not really. Most mATX boards have limited fan headers, fewer DIMM slots, fewer SATA headers, fewer M.2 slots, fewer everything except on the rare few mATX boards or the high end models, in which case you might just as well buy an ATX board because the cost is going to be similar. Smaller form factor cases or cost are the only real reasons to go with an mATX board IMO.
That does seem to be changing somewhat though, for some manufacturers. So it might get better. The Pro4 mATX boards for example, tend to have just as many fan headers, except the -F variant, and four DIMM slots, so there are exceptions.
It's true that most users could get BY with one, but personally I'd never opt for one given my druthers.