I do this, simply because I feel that it is good to know. I can't tell you how many times I've applied a lotion or cream not meant to be eaten right before play and it has somehow gotten eaten or licked, and I like to know if I'm putting something on with the risk of it tasting like sweaty socks, or if it's going to be painless in the taste department. Often, I'll avoid products that may taste disgusting if I accidentally eat them, simply for that reason! Plus, think about all the different types of play there are. You may not want a dildo that tastes gross if your partner might end up having you suck on it!