I'm wondering how secure this method is of securing your laptop or any device that uses this technology.
- Secure the physical device (i.e. if no valid smartcard is provided the laptop won't boot, and the drive cannot be decrypted). This is rarely used as it is a PITA to set up/manage, is vendor specific, and duplicates what Windows provides anyway. This is what HP calls their "ProtectTools."
- Windows authentication: Active Directory can be configured to force certain devices (e.g. off-site laptops) to require a smartcard and to validate the smartcard during login. This stops someone attempting to authenticate with AD or login to the laptop without the smartcard. Combined with Bitlocker, it is fairly effective.
- VPN authentication: This is extremely common. In order to get onto the corporate network you need a smartcard in addition to credentials. This means you physically need the business's hardware to even attempt to break into the VPN (even with stolen credentials).
Many businesses that deploy smartcards are doing #2 or #3, with #3 (VPN) being by far the most common. Combined with bitlocker full drive encryption, and policies that force a password on each wake, it is "good enough" security for all but top-secret levels (and those shouldn't be off-site regardless).
So in answer to your question "secure enough." More secure than not having it.
Well this depends on whether the firmware has been scrutinized and hardened over time, similar to how Yubikeys just get better and better. FIDO and other initiatives are more secure because they have more eyeballs on them