I agree, they do, but it's very recent. For example, 1st gen back on iPhone, 5c is 32 bit, 5s was first iOS device to support 64 bit. Not sure on equivalent iPad devices, but if Roon was 64 bit only, you potentially have 6 month old devices it would fail to run on.

Meridian owner since 1992
Prime & PSU, Focal Elear headphones, Roon (ROCK 8Gi5 NUC), Explorer 1 & 2, F80. 200/203, various Sonos (via Roon).