DIY Bob with digital couplers rather than optocouplers

Very fast optocouplers exist but cost a bit more than slow ones, hence not used on cheap BOB's.
Been quite a while since i used those so can not recall the type and numbers, sorry.
Probably searching Mouser or the likes can narrow it down based on ton/toff.

Are you interested in them for use in a diy BOB instead of optocouplers or for their designed use for SPI and CAN bus isolation respectively?
Note that the first offers only 4 highspeed channels out of 7 with the other 3 being low speed data channels while the second is used for a two wire differential signal.

So I agree with Tommy,I don't see how either would be useful for general pupose IO signals or how you would get any benefit over using a 'regular' high speed optocoupler which are easily available up to 20 or even more Mbs.