I always buy the fastest card I can get at the best price available. Not just for speed but to try to ensure it keeps pace with the changing technology of the video or camera types of the day. The cost difference between the cards is not that great. Especially if you buy one that causes problems be they once in a while (intermittent) or all the time, or compared to the cost of the drone. A slow card is wasted money and it just means having to fork out extra cash in the end. You don't have to buy the biggest when the faster cards do come out, just do with a smaller one/two until the prices drop. I can only speak from owning a canon 5D DSLR and use on computers so far, but the principle I think works for all, unless very old and slow electronic gear.
I have worked in one form or another, with computers from the early 1980s and have followed "get the best" idea within reason for all that time. I am still using a water cooled computer (Intel® Core™2 Quad Processor Q6700) built 12 years ago that is just becoming a pain to use due to more modern program requirements, because I built the best I could at the time.
Buying a slower SD card may seem OK at first, but you may not think that if you do a once in a lifetime shoot and it is lost due or stuttery to the cards slower speed.