Every other class of offering ends with somebody eating something. The burnt offering does not, and that is the whole of its definition. The animal is flayed, jointed, washed and placed on the altar, and the fire takes all of it. The offerer receives nothing, and the priest receives only the hide, which Leviticus 7 assigns to whichever priest performed the rite. In a society where meat was expensive and rarely eaten outside a sacrificial context, a class of offering that fed nobody was a substantial expense with no return, and that is precisely what it was for.
The victim is a male without blemish from the herd or the flock. Where an offerer could not afford one, Leviticus 1 provides for a turtledove or a young pigeon, handled by a shorter procedure at the side of the altar: the priest pinches the head, drains the blood on the wall, removes the crop with its contents and splits the bird without severing it. The instruction is given with the same formula of acceptance as the bull, which is the text making a point about who the system is for.
The olah is also the backbone of the public calendar. Two lambs a day, one in the morning and one towards evening, are burnt offerings; so are the additional offerings of the sabbath, the new moon and each of the festivals, whose numbers Numbers 28 and 29 set out beast by beast. On the great days the additional burnt offerings ran into the dozens. Privately it was brought as a freewill gift, in discharge of a vow, or at the close of a purification, and it opens the sequence when several classes are brought together on one occasion.