Roman Lamps "Research" Collection at Christie's

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Of course we are constantly told that collectors do not collect for any other reason than the noble one of trying to find out about the past. That a collector is a mini (avocational) researcher each of them contributing enormously to our "knowledge about the past". Well here is a modest research collection for sale in the 8 June 2012 sale of antiquities in New York (Rockefeller Plaza), Sale 2565, lot 213:

TWELVE ROMAN TERRACOTTA OIL LAMPS CIRCA 1ST-2ND CENTURY A.D.Estimate $7,000 - $9,000 [...] 

Four black-slipped, one with a figure of Mercury; one with a grotesque, his exaggerated phallus and testicles projecting behind; two with lovemaking scenes, one with the man kneeling behind the woman; and one with the lovers on a bed, the woman's leg lifted to receive her lover;
eight red-slipped, seven of which with lovemaking scenes, one with the woman's legs spread, crouching over her lover in the mulier equitans position; one with lovers on a bed, the man leaning forward to kiss the woman, her back to the viewer, a workshop signature on the base; one on a bed with the man holding drapery in his hands, the woman crouched atop him, bent forward with her head toward his feet; two with the man kneeling to the right holding his lover below her raised left thigh, embracing in a kiss; one with the man to the left, the woman straddling him; one with the man standing to the right, facing left, leaning forward and holding the backside of the woman, his garment lifted, his erect phallus protruding, the woman leaning forward, her buttocks exposed from beneath her cloak, a workshop signature on the base; and one with a bird, its wings outstretched, a snake wrapped around its leg and neck Largest: 4¾ in. (12.1 cm.) long (12) 

The workshop signatures are neither described nor illustrated. These items are all from (it says) "the collection of Alan Dershowitz and Carolyn Cohen". Before that:

 Provenance Seven: Midwestern Private Collector; Christie's East, New York, 28-29 April 1999, lot 690. Three: The Haddad Family Collection of Ancient Art, Christie's, New York, 17 December 1998, lots 40, 41, and 43. One: Anonymous sale; Christie's, New York, 9 December 1999, lot 390. One: with Galerie NAAG, Zurich. The Haddad Family Collection of Ancient Art, Christie's, New York, 17 December 1998, lot 45. 

So what kind of "research" will the happy buyer do on the basis of these lamps, and why can they not do it on the basis of the excellent zoomable image provided for antiquitist titillation by the auction house?

Vignette, learn from a lamp?

Hat tip to PhDiva