Well, if you have an expansionist apartheid state nearby, bent on seeking any pretense to sabotage or get your infrastructure air raided, higher enrichment factors would make much easier to safeguard fuel, given not high enough to easily cause a criticality incident.

Say you have 10 ton of 2.5% enriched uranium to safeguard. If you turn it to 60% HEU, now you have only ~400kg of fuel to safeguard against air raids. Density of uranium is ~19 ton/m³, so that would correspond to just 21 liters of HEU, one bucket worth, what would make it very easy to transport and hide. That would make it possible to split it and store in safe locations, for example, inside some deep boreholes, far apart to each other, making it impervious to attack, for the duration of hostilities. Once they pass, it can be recovered and diluted back to 2.5% with natural uranium, reconstituting your original 10-ton fuel amount.

That’s what their story is.