Me 262 should have been used as a bomber?

[Franek Grabowski]

Roger, you can find various data over the internet, but it cannot change the fact, early jets had poor altitude performance. Lack of pressurised cockpit is not an excuse, as the highest interception of WWII was flown without the one, in a Spitfire IX. Such flights were uncomfortable but certainly possible.
Discussing the performance during interception you must also have in mind time necessary for take off, climbing to the ceiling and finding the target, which is still moving his own way. More, tests performed by British post-war have shown, that Spitfire XIX was flying above range of British radar system, thus remaining undetectable! It was only in 1950 that (Swedish) Spitfire was for the first time intercepted by jets (MiG-15s) but still she was able to escape over Finnish territory. Nonetheless safety measures ceased those incursions.