They don’t mean anything, and they never have.
You may think you can go and make your offer in safety. You can’t.
All bank loan approvals are “indicative”…ie they merely indicate what the bank “might” be prepared to lend. They all have language which lets the bank pull back from the loan and relieves it from any responsibility at all.
Anyone who doubts this can talk to the hundreds of people that bought apartments off the plans in 2006-7, only to find that when the apartments were completed, their bank reneged on the loan approval, changing (for example) from 80% of purchase price to 65% of the then current valuation (which had of course dropped substantially from the global financial crisis)….assuming they were willing to lend anything at all.
Some of those people have lost everything they own as a result. Some are now bankrupt.
Banks are not your friend. They are not loyal. They will not suck up a loss that can be passed on to you. They will not take a risk on your behalf and, to be fair, neither they should. But what they should do is be more up front that their indicative loan approvals are not worth the paper they get printed on. Buyers beware.