[Equackasous]

No, they are not important for the practice of Dhamma and for meditation. Rebirth, and its twin doctrine Karma, are misleading because they can be taken as... "if I do good... then I will..." so Dhamma ends in the same field of any other religious frames where you should do good because the anger of God (Karma) or to have a nice reward, as rebirth in heaven (for a good Christian) or in a better next life which is the same thing at all. The Buddha Dhamma is meant to be practiced because and just because we have understood the Four Noble Truths, the realization about suffering, the realization about a mind that is deluded, that hates and that is greedy and the realization of the way to overcome this mind states. There is no chance to practice the teachings of the historical Buddha with out understanding. An it is understanding which leads to a fruitfull practice of Buddha Dhamma here and now.

Here is a very inspiring sutta about the practice here and now so not to have hopes in a future life...

The First Visible Fruit of the Contemplative Life

"So, lord, I ask the Blessed One as well: There are these common craftsmen: elephant-trainers, horse-trainers, charioteers, archers, standard bearers, camp marshals, supply corps officers, high royal officers, commandos, military heroes, armor-clad warriors, leather-clad warriors, domestic slaves, confectioners, barbers, bath attendants, cooks, garland-makers, laundrymen, weavers, basket-makers, potters, calculators, accountants, and any other common craftsmen of a similar sort. They live off the fruits of their crafts, visible in the here and now. They give pleasure and refreshment to themselves, to their parents, wives, and children, to their friends and colleagues. They put in place an excellent presentation of offerings to priests and contemplatives, leading to heaven, resulting in happiness, conducive to a heavenly rebirth. Is it possible, lord, to point out a similar fruit of the contemplative life, visible in the here and now?"

"Yes, it is, great king. But first, with regard to that, I will ask you a counter-question. Answer however you please. Suppose there were a man of yours: your slave, your workman, rising in the morning before you, going to bed in the evening only after you, doing whatever you order, always acting to please you, speaking politely to you, always watching for the look on your face. The thought would occur to him: 'Isn't it amazing? Isn't it astounding? — the destination, the results, of meritorious deeds. For this King Ajatasattu is a human being, and I, too, am a human being, yet King Ajatasattu enjoys himself supplied and replete with the five strings of sensuality — like a deva, as it were — while I am his slave, his workman... always watching for the look on his face. I, too, should do meritorious deeds. What if I were to shave off my hair and beard, put on the ochre robes, and go forth from the household life into homelessness?'

"So after some time he shaves off his hair and beard, puts on the ochre robes, and goes forth from the household life into homelessness. Having thus gone forth he lives restrained in body, speech, and mind, content with the simplest food and shelter, delighting in solitude. Then suppose one of your men were to inform you: 'You should know, your majesty, that that man of yours — your slave, your workman... always watching for the look on your face... has gone forth from the household life into homelessness... content with the simplest food and shelter, delighting in solitude.' Would you, thus informed, say, 'Bring that man back to me. Make him again be my slave, my workman... always watching for the look on my face!'?"

"Not at all, lord. Rather, I am the one who should bow down to him, rise up out of respect for him, invite him to a seat, invite him to accept gifts of robes, almsfood, lodgings, and medicinal requisites for the sick. And I would provide him with righteous safety, defense, and protection."

"So what do you think, great king. With that being the case, is there a visible fruit of the contemplative life, or is there not?"

"Yes, lord. With that being the case, there certainly is a visible fruit of the contemplative life."

"This, great king, is the first fruit of the contemplative life, visible in the here and now, that I point out to you."

DN2: Samaññaphala Sutta