Exactly. I've been out for weeks on extended deep space flights, and my ship's integrity has been down to 0 for probably half the trip. All things considered, you can just ignore it.
A pity really, I'd much prefer it if it was something to really worry about. IMHO the devs should have made it much tougher, with far more serious consequences, right from the start of the game. It would add a lot of spice if module failures and breakdowns started to happen after about 50% wear and tear, with total failure of some systems almost guaranteed after 0%.
If Ship Integrity were impacted by reckless flying rather than just Distance Traveled In Super Cruise, the whole thing changes in a really good way. Long range explorers would need to be good pilots. If AFMU could repair ship integrity, and if the stat was visible while in flight, then it could be used to mitigate bad luck. We'd have to watch the stat, watch our flying, and have some interesting (maybe even complex) risk to evaluate during our trips. I'd be on board with that.
But right now Ship Integrity is a penalty levied against the player for flying in Super Cruise.
My first long range exploration trip was a little jaunt over to Barnard's Loop and then on to the Spirograph Nebula. As long range trips go it was pretty short. With full scans of almost every system I jumped through my exploration earnings were around 3.5 million. Because I detail scanned over 100 systems my ship integrity was at 30% when I got back home and the repair cost was 1.5 million. That's a pretty heavy tax on exploration as is. If you're going to add to that mechanic the possibility that my ship couldn't even make the return trip, then an exploration trip like that would become a near impossibility.
And that's not a particularly long trip. Forget about scanning planets on the far side of the core. NO ONE would ever be able to do it, not in any significant numbers.