Many people seem not to fully understand the "theory" of tapered pegs.

Since the peg and hole tapers are matched, lifting the peg even slightly out of the hole gives a loose fit that turns easily. Peg dope can make the loosened peg turn more smoothly, but doesn't really do a lot for the holding. You don't need friction between peg and hole while you're tuning.

When the peg is turned to the right pitch, it needs to be rather forcefully (relative to the string forces and structure of the instrument) "jammed" down into the taper to make it hold the position.

If you turn the peg even a few times while it's jammed fairly solidly into the hole, either the pin or the hole - or both - will quickly be reamed out to the point where they don't match, either in roundness or taper or both, and no amount of pushin' and pullin' will make it hold a position.

If either the peg or the hole is "out of round" it won't hold, since any slight motion shifts the peg to where has the most "wiggle" available, or to the position where "all the slack" is taken out, neither of which is likely to be right where you want it.

If both peg and hole are out of round, the peg will have "preferred positions" most likely NOT where you want them, and you'll find it difficult to get the pitch you want, much less hold it.

Tapered (optimally wooden?) pegs can work quite nicely, even for relatively high string tensions; but only if the peg and hole are "perfectly round" and have "exactly matching taper." ("perfectly" and "exactly" being relative terms, of course.)

If you don't learn the "lift - turn - jab" procedure for tuning with tapered pegs, the necessary conditions for tuning to pitch and holding the pitch will disappear with amazing rapidity - especially for strings with higher tension.

The accuracy (tolerances) required for successful peg tuning are probably below what most people can accurately "see;" but visible "score circles" around the peg may indicate a misfit that is sufficient to require some machine work to get to good performance. With peg dope, light "grease tracks" shouldn't necessarily be a concern.

Failure to hold pitch after a reasonably firm endwise push is applied to the peg is an almost certain indication that the reamer and shaver are needed (and or new-fitted pegs).

Personally, I do prefer geared banjo tuners since I'm old and infirm and lazy with poor coordination and a bad ear; but the price differential is substantial unless you include the cost of the occasional "refitting" you probably will need with pegs.

John