TA
I used to refer to the 744 as a big C172. Meaning, all basics are there. You can fly it with just the IAS working. I loved to fly it manual when conditions allowed it, but not to all expense.
If conditions were right, I did it from 15000' or so, anyway with large speed and configuration changes included. Then You really feel how the plane behaves. A "manual" landing with a disconnect from 500' and a full configured, trimmed plane is just barely adding to one's skills.
There are a few points to be taken into consideration however. When the PF decides he/she likes to fly manual, the workload for the PNF dramatically increases, now all settings, even turning the heading bug, he/she needs to do per command, plus checklists, R/T. So You loose partly Yr buddy, and with it his/her backup.
In a busy environment like LAX, ORD or JFK that is not always wise especially during peak hours. However if those are Your homebases, it might be different.
PAX paid their tickets to get there the safest way. That too much automated flying erodes pilot skills is not their problem.
Tired after a long flight, marginal weather during the approach, are valid enough to make a wise decision and skip yr "training" to the next opportunity.
Using GA flying as a surrogate not completely replaces manually flying an airliner. And it is not w/o danger, each year airline pilots loose their life in GA planes. In about 40 years of commercial flying I lost at least five friends/colleagues in GA related accidents, "only" one to an airline accident.