No

So far I've found, calcium levels up to 5 times normal pool, evaporation 2 - 3 times higher, up to 30% more chlorination and significantly more acid....

I am not a pool designer but with every infinity or knife-edge pool I have encountered, all the "lost" water - what cascades or falls over edge - is collected and recycled back into the pool. I am not sure how that would escalate calcium, chlorine or evaporation rates to the extent you mention.

In an arid climate the simple act of falling/splashing water can greatly increase water loss from evaporation. I'm no pool chemist, but that same evaporation in an arid climate can cause chlorine loss as it changes to a gas or salt deposits if it is a salt based pool.

You have a three foot drop to work with. Does that make it an infinity edge to the lake only when you are in the pool? Will it be an infinity edge when you are actually spending more time sitting on the deck? If not, then it is not worth the extra cost.

Thanks for the replies. The waterfall causes evaporation at a way higher rate than a conventional pool. Only the water evaporates so the calcium etc in the water is left behind and as a ratio it has to increase. Not an issue since you’d be aware of it when you regularly test your water.

I've heard a lot more than $30k additional, but than can vary regionally. The infinity edge is a purely aesthetic/design choice so "worth it" is subjective. If you have the budget to where that additional investment isn't going to affect you, and aesthetics are important to you, it's probably worth it. If it would be nice but you'd probably like a $30k upgrade to your outdoor kitchen better, and you're not comfortable paying for both? Probably not.

I will say that the infinity edge is a feature that has - for better or worse - gotten value engineered out of every single pool project we've designed with one. As we work our way through the landscape design it's the easiest line item to cut to get something else.