Thermal cracking (TC) of the Athabasca vacuum residue (ATVR) and its deasphalted product [deasphalted oil (DAO)] was studied. A comparison of conversion and product properties between TC and ultradispersed catalytic steam cracking (CSC) upgrading of both feedstocks is also reported, using K-Ni catalysts. Thermal conversions with stable products for the deasphalted fraction (DAO), reached 20% (w/w) higher values than the ATVR. DAOCSC provided 8% (w/w) increased conversion compared to DAOTC, with stable products. Higher thermal conversions for the DAO compared to the vacuum residue were explained in term of the better properties determined for the asphaltenes produced in DAO upgrading, i.e., higher hydrogen content and better solubilization properties due to lower molecular sizes, solubility parameters, and aromaticities. A definitive link between the nature of produced asphaltenes and products stabilities, as measured via P-value, was found. Higher DAO-steam catalytic conversions with stable products were also obtained and rationalized based on the occurrence of water splitting into *H and *OH radicals and hydrogen production from steam reforming/steam cracking reactions occurring during CSC processing. The inhibition of hydrocarbon free radical recombination (coking) by *H capping and hydrogenation facilitated by Ni catalysts are believed key reactions occurring, leading to better DAO product properties. Exploratory evidence gathered with the NiCeMo CSC-catalyst for whole bitumen processing added support to the later findings, i.e, olefin production inhibition was evidenced, indirect evidence of hydrogenation occurrence. A convenient field upgrading process that avoids distillation or separation (deasphalting) carried out at low T, P is, thus, envisaged.