And they should really use OP_RETURN, not a Taproot hack.
Even better: they could use OP_RETURN inside TapScript (and then stop worrying about any size limits, except those enforced by separate network for ordinals). Then, the owner of a particular Taproot address can always reveal TapScript in some ordinals network, while it will be guaranteed that this TapScript will never be pushed on-chain. And then, other TapScript branches or spend-by-key can be used to move those ordinals.
op_return is another dead weight store but not a proof of transfer
however bitcoin does have a way to store a 'file hash' and spend it in a provable way.
thus not needing to use op return nor witness weight to store whole files. and instead have a tx with average tx size that can prove a 'file hash' and prove its transfer