It’s the same as with rewards eligibility, I guess. Why is the protocol stronger with 10% threshold? Because RPL is a part of the protocol and this threshold aligns RPL holders with its growth. This is important especially given the recent motion to Allow minipool deposits while under “min” RPL. Some folks might stop caring about the protocol as a whole (specifically its RPL part and its future) at some point and still suck profit out of it. Not going to say that this RPL minority can accumulate into a big voting power, but if all other pDAO is divided one day on some topic, this force can play a significant role.
I agree that it’s inconvenient that voting snapshot is made ad-hoc, so voting power is more prone to market volatility than it is with rewards. I like your suggestion to meld vote and rewards snapshots.
As for RPIP-4 contradiction, I think that since pDAO voted to depend on smart contract function, that is controlled by oDAO solely, than it’s NOT necessary to have a special vote (regarding voting power below 10%), which have to include all excluded by Atlas upgrade. I agree, however, that this is wrong for pDAO to depend on oDAO and hence the wording in RPIP must be fixed.