NavList:

As an ignoramus who read the classic textbooks on Mercator and other projections, I understood Mercator under classic dogma to be "best" for local charts of small geographic area due to the ease of straight line navigation and parallel lat & lon lines. On small areas, distance distortion was within "acceptable" limits.

Same explanations typically go into gnomonic, conic, polyconic, etc.

Gnomonics were quoted "best" for great circle problems.....

From the comments, I am afraid my understanding may be lacking.

Can someone help me out with the understanding of charts for small geographic areas, if the Mercator is functionally obsolete.

Remember that I am still a devotee of local hard copy  charts and plotting skills as my insurance against oversights or loss of the GPS displays on my dashboard. My navigation is mostly point to point coastal in all conditions of vis. This means I still use dividers and paralells or other simple visual aids to ensure I know what I am doing. (I do admit a love of radar).

I do not have a detailed understanding of modern mapping.