There is some merit in thinking "if it's not breaking in two years, it won't break in three".
The oldest drive I have is a 3.5" WD Blue from the 00s, still working after 2,562 power-ons and a total power-on time of 1,233 days (well over 3 years on and operating). Every drive of the 20-or-so I've used, bar one relatively quick failure, has been as reliable. This experience - combined with the data security perspective (medium's reliability, sensitive parts retention) - is why I think an HDD should last at least 2 or 3 generations, as in 4-6 years. It can and should be the case.
Seagate's 5-year standard warranty on all drives recognised this, and I preferred them for it. Used to love their "SeaShells", too, whereas now every maker uses a glorified bin liner.
No matter how you look at it, though, a product's warranty is a direct indication of the manufacturer's confidence in their product standing the test of time. In this case, a whopping 50 % extra part service life, GUARANTEED, on a critical (4 TB is a lot of data) system component is quite the boon for a marginal sum of money, or no extra at all, whether it's for your own peace of mind or for the sake of resale value. We're not even approaching diminishing returns here, especially with products this close in performance (speed and silence wise).
As an extra consideration, longer warranties mean better service for the consumer and potentially less waste. Purchasing decisions matter.
Case: FD Define Mini
Parts: P8Z77-M Pro µATX, N650Ti-1GD5/OC, G.Skill 2x4/1600/CL9 DDR3U, Xonar DX, WD G 1 TB, m4 128 GB, RX-5300 PSU
Cooling: Noctua NH-U12P SE2 + Scythe SS PWM, 2x Noctua NF-P12
Extras: Eaton UPS, Dell 24" EIPS, Ducky TKL kb, SteelSeries m, Synology DS213j 3+3 TB RAID1
idle & load: CPU 32 °C & 44 °C @ 300/600 & 600/800 RPM, GPU 35-65 °C @ 1200-1650 RPM