It was important to the events of LOTR, though. The events of The Hobbit took Smaug and the Goblin/Orc forces of the Misty Mountains out of Sauron's plans. Without this, there would have been devastating war in the North as well as in the South. Although the Men, Dwarves and Elves of the North didn't help much with the defense of Helms Deep and Gondor, just by being there they meant Sauron had to reserve some of his forces to deal with them later. It was only the Witch-King of Angmar and the Orcs of Minas Morgul (reinforced by Men from the Far South and East) that were sent against Gondor, not Sauron's personal army from Mordor. Sauron had to reserve those for dealing with Lothlorien, Rivendell and the North.
This quote from LOTR, Appendix A, describes Gandalf's thoughts just before meeting Thorin by chance in Bree:
But at last there came about by chance a meeting between Gandalf and
Thorin that changed all the fortunes of the House of Durin, and led to
other and greater ends beside. On a time Thorin, returning west from a
journey, stayed at Bree for the night. There Gandalf was also. He was
on his way to the Shire, which he had not visited for some twenty
years. He was weary, and thought to rest there for a while.
Among many cares he was troubled in mind by the perilous state of
the North; because he knew then already that Sauron was plotting war,
and intended, as soon as he felt strong enough, to attack Rivendell.
But to resist any attempt from the East to regain the lands of Angmar
and the northern passes in the mountains there were now only the
Dwarves of the Iron Hills. And beyond them lay the desolation of the
Dragon. The Dragon Sauron might use with terrible effect. How then
could the end of Smaug be achieved?
The end of Appendix A describes the tactical importance of the Battle of Five Armies:
The Dragon was slain by Bard of Esgaroth, but there was battle in
Dale. For the Orcs came down upon Erebor as soon as they heard of the
return of the Dwarves; and they were led by Bolg, son of that Azog
whom Dáin slew in his youth. In that first Battle of Dale, Thorin
Oakenshield was mortally wounded; and he died and was laid in a tomb
under the Mountain with the Arkenstone upon his breast. There fell
also Fíli and Kíli, his sister-sons. But Dáin Ironfoot, his cousin,
who came from the Iron Hills to his aid and was also his rightful
heir, became then King Dáin II, and the Kingdom under the Mountain was
restored, even as Gandalf had desired. Dáin proved a great and wise
king, and the Dwarves prospered and grew strong again in his day.
In the late summer of that same year (2941) Gandalf had at last
prevailed upon Saruman and the White Council to attack Dol Guldur, and
Sauron retreated and went to Mordor, there to be secure, as he
thought, from all his enemies. So it was that when the War came at
last the main assault was turned southwards; yet even so with his
far-stretched right hand Sauron might have done great evil in the
North, if King Dáin and King Brand had not stood in his path. Even as
Gandalf said afterwards to Frodo and Gimli, when they dwelt together
for a time in Minas Tirith. Not long before news had come to Gondor of
events far away.
‘I grieved at the fall of Thorin,’ said Gandalf; ‘and now we hear that
Dáin has fallen, fighting in Dale again, even while we fought here. I
should call that a heavy loss, if it was not a wonder rather that in
his great age he could still wield his axe as mightily as they say
that he did, standing over the body of King Brand before the Gate of
Erebor until the darkness fell.
'Yet things might have gone far otherwise and far worse. When you
think of the great Battle of the Pelennor, do not forget the battles
in Dale and the valour of Durin's Folk. Think of what might have been.
Dragon-fire and savage swords in Eriador, night in Rivendell. There
might be no Queen in Gondor. We might now hope to return from the
victory here only to ruin and ash. But that has been averted - because
I met Thorin Oakenshield one evening on the edge of spring in Bree. A
chance-meeting, as we say in Middle-earth.'
Or maybe the hand of Ilúvatar (Eru).