I meant that Ukraine managed to breach the porous Russian air defense on several occasions. They didn't have long range missions to hit the bridge, but the hole in the sky was open. Now they have long range (300 km) ATACMS, now the bridge can likely be brought down.
They're able to breach air defences around Crimea through a combination of overwhelming the defences with drones, using drones/decoys to reveal and then destroy radars/launchers, and spreading drones across a wide area to look for areas lacking in coverage. However, the closer you get to the Kerch bridge the denser anti-air is likely to be, so the above strategies only get you so far. You also potentially have to hit a single support multiple times to have an impact and ATACMS are only accurate up to about 10 metres, so they'd really have to launch a lot of them to stand a chance of taking the bridge out long term.
There are a few potentially big benefits to ATACMS that I'm aware of. The first is that stockpiles all the way up to the coast should be in range for Ukraine, meaning they could go back to destroying equipment before it reaches the front. Another is that there are cluster variations of ATACMS, which can be (and have been) dropped on Russian airfields to take aircraft out for the foreseeable future. I think they also carry a bigger payload than Storm Shadows, which makes them better at blowing up unfortified buildings and storage areas, but I'm not 100% on that.
Hopefully they arrive in large quantities, that's probably been the biggest issue with Storm Shadow/SCALP missiles, the numbers are limited.