At issue here is the fact that dietary fat is not water soluble. It's like oil and water, which has the practical effect that it couldn't be carried through the bloodstream.

That's what the chylomicrons are for. Package the trigs into a form factor that can be carried through blood circulation.

Likewise, also note that the triaglyceride is a form specifically chosen because it is too big to diffuse through cell membranes. Fatty acids free of their glycerol backbone will diffuse straight through a cell membrane and into circulation.

The key to that process are hormones: Insulin, LPL, HSL, and signalling factors like Leptin.

Specifically, insulin acts like a break on LPL and HSL. Within adipocyte cytoplasm, HSL is the hormone that will break down a triaglyceride into its constituent fatty acid parts + glycerol. Outside the cell, it's LPL. When insulin levels are high, LPL/HSL expression is reduced, and when insulin levels are low, it is increased. In fact, the dangerous condition diabetic ketoacidosis is caused by a total lack of insulin allowing HSL/LPL to act without restraint, and that allowing for an uncontrolled outpouring of converted free fatty acids from fat cells into the bloodstream.

The system of fat recycling works to supply a constant fatty acid fuel to cells that need it. You eat dietary fat, it gets packaged for transport, and enters the bloodstream exactly like Dr. Fung (above) says. If a cell needs it, it can perform lipolysis using LPL and break down the trig so that the fatty acids can enter the cell. If not, then the trigs can continue to flow through circulation.

Both the liver and adipocytes can convert/de-convert triaglycerides into fatty acid and back into triaglycerides.

In a functioning system, the direction of fat thus isn't unidirectional--as in it only goes into fat cells for storage. It should also be able to leave fat cells for use. In fact there should be a constant influx and efflux from the adipocytes. All of this process of fat utilisation and oxidation governed by hormones which should inter alia maintain energy balance and stable body weight through upstream hormonal changes.

It's only when the system has become deranged that the direction of fat becomes influx only. One of the chief goals of the keto diet is to fix that issue by suppressing the secretion of insulin and its effects of lipid metabolism.