Many of the one-bag advocates are bizarrely militant, insisting that the one bag be literally one bag, with no personal item unless it fits into the one bag and will only be taken out once aboard the plane, or if you're forced to check the bag, which can happen if there's no overhead space left, or if the bag is weighed and found to exceed a particular airline's limit. For example, my main bag often weighs almost exactly 8 kg, which is OK for every airline on which I've flown but too much for some others.
I do it partly for convenience, and partly to avoid a checked-bag fee. Many FlyerTalkers probably have a free bag allowance because of status, or because of having the airline's branded credit card.
But I only do it when it is convenient. I have two trips coming up in which I'll check a bag, one because I need a bag large enough for hiking gear, and one because the trip is too long for the clothing that will fit into a carry-on bag and the schedule is too full for doing laundry.
Whether it's feasible also depends partly on the size of your clothes and shoes. It is harder if you wear large sizes.