Are there other similar patches on Mars where water could be found? What significance does this discovery hold for human exploration, particularly for settlement on the planet?

Not quite. This area is one of the most suitable for such findings, thus the initial search

A crew with tools could extract water for in-situ resource utilisation from ice in regolith (unconsolidated residual or transported material that overlies the solid rock on the earth, moon or a planet) or, in the case of a near-polar landing, from

ice itself. There would be no need to drill or dig 1.5 km of polar ice to get to the salty water (that would need, most likely, to be desalinised, too). There are far easier ways to reach reservoirs on Mars.

Besides, just like Earth, melting ice on Mars is technically not a problem, compared to the very complex operation to physically reach those lakes. On the other hand, if these bodies contain liquid water (and to a large extent even in the previous scenario of “just” extracting and melting water ice in caps or regolith) there is a planetary protection problem (NASA defines “planetary protection” as the practice of protecting solar system bodies from contamination by Earth life and protecting Earth from possible life forms that may be returned from other solar system bodies), which is not an easy one to solve.

In any case, we talk of limited resources on a planet that cannot, most likely, sustain large-scale populations. For a small settlement in need of H2O for life support systems or propulsion, probably using other near-surface reservoirs is far better.