SG bundle their cameras with the Sandisk high endurance cards, i have a few of them too in my test suite of memory cards and i quite like them ( not least that they have warranty when used in dashcams )
As i recall SG will honor warranty on the bundled cards, but of course so would / should any dealer where you procured the same card, i dont think SG bundle some cards just to make more money off you, but TBH i have not looked at the price difference in cameras without / with some memory card.
Other brands with their own brand memory cards, you can get to pay a premium for those cards.
Sadly the chance of getting a less suited memory card are always there, even if these suckers are standardized, i have seen cards with 30 MB/s write speeds not being able to handle a camera that barely write 5 MB/s
When i got into dashcams the lexar brand was highly recommended, but after they changed hands and changes was made they are no longer recommended.
By now i have had any brand memory card die on me, and some horrible fast, but was then able to get RMA, but still extra work.
When done testing a system in my car i often continue to test static in my south facing living room window sill, with the power source being a wall wart and then have a timer on the mains side of things to simulate several start / stop events during the day.
These static test cameras get about 10 hours a day, so that do hit the memory cards in them when the camera sit there in my window for a few months.