How much does SD card speed/durability matter?

Sorry it's simple, and I wasn't sure if it even belongs to another section and I tried searching for it. Some say RAM logging, others that it isn't needed and may create more issues.

I can actually turn off the logging completely, for me it's largely set it and forget it. It may be nice to see a little info like the main landing page though I'm guessing that's in RAM? Anyway I'm willing to sacrifice that.

The other related question is whether the speed of the card matters at all. I'm considering getting a pack of smaller, slower, name brand cards say class 4/6 cards instead of a U1 - would that even matter in terms of performance? Also being cheaper if it dies it's really nothing to replace it.. Thanks.

If its just Pi-hole that you intend to run on the Pi, get a cheap one but not the cheapest.
I agree with most brands being compared in below link:

The one for my Pi-hole setup is already several years old and no issues so far (no log-to-ram etc).

I have had good success with SanDisk Ultra 32 GB cards. About $8 US at Amazon. Zero failures for me in constant use over several years.

A larger capacity card will provide more space for wear leveling. I would avoid the smaller cards.