Yes it does effect you vote weight and value of you upvote. However as you share you vote you help to increase reward pool for all steeemians and help other people and yourself grow via curation. 

When you don't use your vote you are sitting on idle power that is not doing anything for anyone. You want to manage you vote by casting more votes with less vote % applied to the weight and cast more votes than not using it at all. 

A few platforms and plugins allow you to do this by doing this you are casting more vote and helping more people without sitting on idle power.