Why do some people take umbrage, because someone disagrees with their opinion ?
The OP asked peoples opinion on a scope for two very different scenarios. "Cost" is secondary to whether a 2.5-10 x 56 is a good choice.
We also have to recognise that whilst some have good vision, others will want, need, require a higher mag, to be confident with a longer shot, and the person to make that decision, is the person doing the shooting.
I have only been on one plains game trip, and "I" would not have been happy with a 10, or 12 power scope.
I'm very lucky, and I have a passion for driven boar. I shoot open sight on a tight peg, and a 1-6 x 24 if the peg is open. I would not want to be acquiring a running boar, close up, with a 2.5 mag scope. I had one peg last trip, where I shot 4,
longest shot, about 10yds.
With regard to cost, final choice will be dictated by budget, but if I were paying $6000.00 - $10,000 to shoot a cape buffalo, I would not be compromising on the scope, any more than I'd want to turn up with a .243