Having a basic level of cardiovascular conditioning is vital for all of us. Whilst it's understandable that we all have different goals, having a level of health that supports longevity in achieving those goals is more than a little important.
Good cardiovascular conditioning protects you from a number of health conditions, which will not only shorten your life, but will drastically reduce the quality of that life & will rob you of your ability to do your sport.
The diagram below, from the World Health Organisation, charts the biggest killers of people in middle to high income countries (pretty much the western world).
At least 5 of these (CHD, stroke, pulmonary disease, Alzheimers & diabetes) are positively influenced by better cardiovascular health. It could be argued that there are others on the list that are too.
As mentioned above, cardiovascular exercise can have a protective effect against developing type 2 diabetes. It's important to note that exercise by itself will probably not be enough; there is a dietary component too.
Those who eat high amounts of sugar & starchy carbohydrate are definitely still at risk. Whilst not suggesting that you can eat whatever you please as long as you exercise, looking after your cardiovascular health will negate a small amount of poor nutrition.
Alzheimers is also mentioned above in relation to the chart. Recent studies have suggested that exercise may be protective against dementia. I'm all for long life but only if I have quality of life. It would make sense to make every reasonable effort to stave off what is a very nasty condition that would rob you of life quality in your later years.
Good cardiovascular fitness results in increased ability to recover between bouts of heavy exercise. Whether it's some sort of interval training, heavy lifting or any other intermittent intense exercise, having better basic cardio means better performance later in the session.
It just makes you feel better for life in general. And who doesn't want to feel good?