Does it have any effect on the car if the wheels are not straightened?

Yes
If the wheels of a car are not aligned, it does have a significant impact on the car. The main impacts include:

Tire damage: If the wheels are not aligned for a long time, the tires will be deformed, especially the sidewalls of the tires will be under greater pressure, which will accelerate aging and deformation, and in severe cases may cause air leakage or tire blowout. 12
Steering system damage: If the wheels are not aligned, the steering rod and other related components will be under continuous stress, which will accelerate the aging and metal fatigue of these components, and may cause the vehicle to run off the track and abnormal tire wear. 12
Suspension system damage: If the wheels are not aligned, the rubber components and elastic struts of the suspension system will be under stress for a long time, which will accelerate wear and eventually damage the suspension system. 23
Therefore, in order to keep the car in good running condition and extend its service life, it is recommended to align the wheels when parking.