Is using numbers to memorize words a good idea?

During the learning phase or during memorization? If it is the former, wouldn’t this method actually take less effort and time than a bestiary since it wouldn’t require searching and learning new images? If it is the latter, may I ask why that would be so? The calculations would be necessary only in the learning phase. After a while, the connection between images and pairs of letters would become immediate, wouldn’t they?

Sure, I would love to do that for all words, but sometimes words don’t have obvious counterparts. Only in these cases I’d like to apply this system. Do you think it would be bad even in these cases?

I’m not sure about that. I’m currently practicing my 3-digit list of people and am about to finish my 3-digit list of objects, so I wouldn’t say I’m delaying progress.