I had a sump pump in the basement of my house my house and it ran very little.
Typically during a long heavy rain, it would run for 45 seconds or so, then turn off for 5-10 minutes, then repeat. It would not run for weeks as well. They aren't designed for extended continuous usage as other types of pumps might be and while some types can be submerged and can run non stop for a while, they will not last years like an aquarium pump if used that way.
Some submersible ones also have temperature maximums that are too low for tropical aquariums. Note that home sump pumps are often designed to pump groundwater which almost always will be in the 35-55 F range. Pumps with a 70 F maximum (and yes some have those) would be fine as a groundwater pump, but not for a tropical aquarium.
The oil leakage issue is 'probably' not a concern as generally speaking intentionally leaking oil into groundwater near urban dwellings would be an EPA violation, but the amount from a sump pump 'might' be small enough to pass EPA thresholds. That amount 'might' still be enough to be a hazard to fish.
In short, not a good option for aquariums as the design applications are sufficiently different as to make it inappropriate.