Helsinki works for a southern circuit. Compare a later rental if the first part of the holiday is a city stay.
Finavia locates airport rental service points in the arrivals hall and describes vehicle collection in P3B. Nearby off-airport companies can use different arrangements; follow your own voucher.
A car is useful for rural lake accommodation, national-park approaches and independent travel beyond the main train routes. Helsinki city days often work better before collection. Lapland is a separate regional choice, especially in winter.
Compare airport collection with a later collection if you start with a city stay. Include the transport to a different rental branch and any extra parking nights when comparing the total cost.