Road tire coming apart in the middle, is it safe to ride?

Those look pretty dried and cracked. The main worry for me is grip. When the tires get like that, then the grip goes down. My understanding is that as long as the casing is intact, the tire isn’t actually in more danger of getting a blowout, but you will be more prone to punctures and crashes going around corners. After taking spill due to a bad rear tire, I’m now super careful of my tires, personally. Keep them clean, dry, out of the weather, heat and cold and keep them inflated. But when the compound dries up like that, it’s on its last legs, unfortunately.