I had a 2004 EG for 11 years - got the 'I wants' for a Oil Temp gauge - after it was on for awhile - I never really looked at it and the times I did really watch it on a hot day - in all those years and 82K mles (and in some HEAT) What did it really matter - Hey, it looks cool but 'Really' Not needed - but, Hey, its your $$ and life is short, lol
This is on my wish list, but not at the top. I'm with the guys that say what you don't know won't hurt you. I try to avoid traffic like the plague and have done pretty good in almost two years I think my fans have only come on one time that I recall. My fans get the most use right before I park it for the night, I do the pump/fan check for a minute or so til I see the temp drop to about 170*-175* then I put it to bed. For me I don't think high oil temps is a concern, but agree it would be nice to have for peace of mind.