Couple of reasons. Primary one is GPM from your tractor. I'm not sure how much the BX puts out, but since the OP appears to have done his research regarding how much flow he needs I'm assuming it doesn't put out enough. My L1500 puts out 2.8 GPM. You'd measure cycle time with a calendar. Most of these compact tractors run around 2000 PSI, so if you'll need to step up to a bigger cylinder to get the same force as something running 3k making problem 1 worse.Any reason to not just run one with a power beyond kit (Backhoe hydro)? Or if you want to mount something to the loader the 3rd function would work as well...?
I ran the Tractor supply 3pt splitter with my B3030 for a long time and loved it.
Something like this from HD
https://www.homedepot.com/p/Boss-Industrial-3Pt-22-Ton-Horizontal-Vertical-Log-Splitter-3PT22T25/304845095?mtc=Shopping-B-F_Brand-G-Multi-NA-Multi-NA-Feed-PLA-NA-NA-Catchall_PLA&cm_mmc=Shopping-B-F_Brand-G-Multi-NA-Multi-NA-Feed-PLA-NA-NA-Catchall_PLA-71700000014585962-58700001236285396-92700010802552439&gclid=Cj0KCQjw0pfzBRCOARIsANi0g0vXGrNQWiKd5Z0DgoD4oalyA3gb7z1_um_o2fdOUcUVth3_IVbewZUaAltWEALw_wcB&gclsrc=aw.ds
Not relevant to this thread because he's talking about running the splitter with a PTO, but a lot of folks like to have their tractor free to use the FEL to handle wood rather than run a splitter, which would drive the decision to a self powered splitter.