quite expensive on Amazon
I think that's just a function of the specific sellers on Amazon and there being little competition (few sellers) for the product on Amazon. Now, this is a bit moot as since noted above Kendall is no longer promoting its oils as having titanium and there is no longer a titanium field in the PDS for the new LiquiTek oils, but having looked at Kendall a lot recently (though for 20w-50, not these grades below), I don't think there's been a material change in pricing in going from Liquid Titanium to LiquiTek, so I will use the new LiquiTek prices as a proxy for the old Liquid Titanium prices.
Pricing wise LiquiTek generally seems to be about $4.70 per qt (including shipping), which seems to be only slightly higher than retail prices for Edge (per walmart.com). Specific pricing differences may differ by product (syn, grade, etc.), but these below appear to be direct competitors:
kendallmotoroils.com (run by PSC which also sells Kendall, kendallmotoroils bundles shipping into higher unit prices, the PSC site has shipping separate, so lower unit prices, but the total cost is similar once shipping included)
Kendall GT-1 dexos1 Full Synthetic 5w-30, Gen2 | 12/32 Ounce Bottles: $56.30 (no shipping charge, shipping included) = $4.69 per qt
walmart.com
Castrol EDGE 5W-30 Advanced Full Synthetic Motor Oil, 5 Quarts: $22.38 = $4.47 per qt
obviously with Kendall you need to buy more as part of getting the price.
As has been noted, Kendall appears to target selling bulk oil to shops or large customers, etc. So I don't think they intend to sell to individual retail customers (especially with sister products like MC filling that space), so they don't intend to answer the question of why someone would choose Kendall over a comparable retail product, and I don't think there is a reason for most people to go through the trouble of getting Kendall vs Edge or another comparable oil
However, I am attracted to Kendall's GT-1 Competition Motor Oil with LiquiTek 20W-50 b/c it's the only _conventional_ 20w50 API SP oil I know of that has higher Zinc (0.120) and Phosphorus (0.109). Valvoline VR1, which has a bit more of each, which I have no doubt is suitable for street driving, doesn't carry an API rating. Also, depending on where you can source it, Kendall's GT-1 Competition 20w50 is at least ~30% cheaper than VR1's best retail price in my area (no menards where I am) of about $6 per qt (5 qt jug), and you if can get Kendall via local pick up at a distributor, it may be only $3.50 per qt (haven't had a chance to contact my distributor yet)