Just about everything I have ever driven has an oil cooler. I think it's a german thing.

220 is a good oil temp, 240 is a little hot, 280 is too hot. Ask me how I know? Well... Porsches, VW's, etc.

In a water cooled engine, it's unlikly you'll ever see 280 on the oil temp guage, unless you're racing, or your radiator is dry. Water is the primary coolant in water cooled cars. They cool the oil because with piston squirters and turbo's, it can get too hot. A simple cooler solves that.

If you're going to putter around, I can't see how disconnecting the oil cooler will matter. If you're in the desert, or autobahn, or maybe a three hour cruise, then it may matter. I'd bypass the cooler in a pinch, otherwise, I'd fix the hoses.