If a person has to go through 58 pages (as you claim there are, I haven't ever seen logs like these) they'll be loading the pages alot. I'm not sure if that would affect site load more than just searching once, but it sounds like it.
I suppose adding a search function might affect site load aswell, as it would encourage people to look through their logs more often, rather than being lazy and not doing so.
To me, this is quite a useless feature as I'm not ever going to be searching through Guild Logs (I don't think so anyway

). Then again, if enough people want it and it wouldn't do too much damage to site load, why not?