The max speed of the V22 is about 290 mph.
The max speed of the UH 60 Blackhawk is about 183 mph.
The max speed of the Apache Helicopter is about 176 mph.
The V22 can carry a heavier payload and fly higher than the listed specs for the V280.
However, a mission such as S.A.R. (Search and Rescue), speed is very important along with range.
For example, you have some injured people 100 miles away. It would take more than 30 minutes each way in the V22 and much longer than that in the Blackhawk.
Calculated time for 200 miles (round trip):
V280 would be about 60 minutes more or less.
V22 would be about 1 hour and 15 minutes more or less.
In a rescue operation when someone is injured, getting the person to proper facilities and the time to do that would be critical to saving the life.
By having multiple platforms with multiple different capabilities allows commanders to choose the platform (capability versus mission requirments).
The V280 should have a smaller RADAR footprint than the V22.
Just a different factor in usage...
Worth mentioning that among potential opposition equipment, the Mi-24 Hind and variants can go 208mph and can perform many of the functions of the Blackhawk and Apache (for those that don’t know, it’s a gunship like the Apache, more heavily armored than the Apache and it can carry 8 troops under armor while doing it).
Among other missions, having a craft that can fly in, insert troops and run the hell away from any reaction forces carried in Hinds would be really nice considering just how many countries that don’t like us fly Hinds.