North Gaza is being strategically bombed in order to destroy Hamas' tunnel network they built under civilian homes and infrastructure ahead of the ground incursion. See map courtesy of BBC.
Hamas use these tunnels to store weapons, hide in and even to use as a bottleneck against Israeli military which would be like shooting fish in a barrel for Hamas. Hamas also use tunnels as an escape route as well as an entry point into Israel.
Any tunnels still operational after that will be destroyed by the Israel Defense Forces during ground incursion by throwing explosives into them.
As far as National Security perspective goes, you can argue that it was a mistake for Israel to withdraw from Gaza in 2005.
Reuters explains what happened:
"Security in the area around Rafah is also of concern to Egypt because Sinai has been the site of an Islamist insurgency that flared a decade ago. Hamas, which has run the Gaza Strip since 2007, shares the Islamist ideology of the Muslim Brotherhood, a movement outlawed in Egypt."
And:
"Hamas' deadly attack on southern Israel six days ago - unprecedented for the group in its planning and scale - was a devastating demonstration of the military expertise it has gained since seizing control of Gaza in 2007....
Necessity is the mother of invention," said Ali Baraka, a senior Hamas official, adding that the group had long drawn on money and training from Iran and Iranian regional proxies like Lebanon's Hezbollah, while bolstering its own forces in Gaza.
Difficulties in importing weapons meant that over the past nine years "we developed our capabilities and are able to manufacture locally", said Baraka, who is based in Lebanon....
In the 2008 Gaza war, Hamas rockets had a maximum range of 40 km (25 miles), but that had risen to 230 km (142 miles) by the 2021 conflict, he added.
After the most recent Gaza war in 2021, Hamas and an affiliated group called Palestinian Islamic Jihad managed to retain 40% of their missile inventories, a key target of the Israelis, according to the U.S. based non-profit Jewish Institute for National Security of America, keeping roughly 11,750 missiles compared with 23,000 before the conflict."
www.reuters.com/world/middle-east/bombardments-hit-area-gaza-sinai-border-crossing-gaza-officials-2023-10-10/
So, as a result of Israel Defense Force pulling out of Gaza in 2005, Hamas ended up in power just two years later. And increasingly improved their weapons capabilities whilst increasing their total membership from 10,000 in 1990 to 40,000 in 2023.
It's quite clear that Israeli withdrawal from Gaza made things worse from a National Security perspective.
Not better.
By now, it should be clear that it's NOT an option to allow Hamas' terrorist infrastructure in Gaza to remain intact.
What alternatives do you suggest that will deal with the security threat Hamas has continued to pose Israel?
They've become more sophisticated and massively improved their weapons capabilities since Israel withdrew in 2005.
Iran has Israel surrounded by its proxies, Palestinian terrorist groups, all ready to attack according to the Ayatollah.