That offer sounds reasonable.
The oil consumption issue is limited to 2012 and early 2013 Insights. A 2010 will not lose any oil at all.
Hybrid battery failures are highly uncommon with the second gen Insight, maybe a couple from very hot climates.
Mileage is no concern for the battery; long periods of disuse is.
The OEM 12 Volt battery is a known weak point. Have it replaced when you are in doubt, monitor its voltage anyway. But they are cheap.
I expect a 2010 to be already on its second 12V battery.
Make sure the service history is complete.
Check for CVT fluid changes and the spark plug change. The Insight uses 8 iridium plugs which last very long but are not cheap to replace.
When you do a test drive check whether the transition from low speed to higher speed (around 10 to 15 mph) and vice versa is smooth. a slight bump is common, a stronger jerking or shuddering is not. These often clear up with a proper CVT fluid change - but not always.
At speed check for a high-pitched whine around 60 mph. Mine does that, while most other Insights don't. You would not notice it with the radio on, it is not that hard - but I'd rather not have that anyway.
When hit with side wind at or above 50 mph there can be a burring sound from the top windscreen seam if that is not tight. Should be an easy fix with kit, but again - better to have one where the seam is tight.
Check out the rims and tires.
The Insight is sensitive to tire pressure, especially when it is lower than standard.
Many find handling improves with slightly higher pressure than the door sticker advises.
185 mm width tires on 16 inch rims are noticeably more precise than 175 width 15s which were OEM to 2010 Insights. The ride is more firm, economy nearly the same.
The Insight horn and halogen low beams are not impressive. I replaced them with an Accord (high tone) horn and cheap Chinese HIDs which works out quite well. LED grids in the dome and boot lights are an easy improvement too.
The Insight is a reliable car, good value for money.
Have a look around, do some searching.
Post a picture when you do buy it