To be honest we sell SS drip trips and Titanium drip tips. If I hold the same drip tip in the two metals next to each other you can't visually tell the difference until you hold them. Then the weight difference immediately tells you which is which. But they look pretty much identical.
When you polish stainless steel to the point that it outshines chrome, there will be nothing you could do to the grey titanium to make it
match exactly the blue stainless steel--especially for the kind of fanatic that polishes a steel mod multiple times a day. It's not as obvious as the difference between sterling silver and silver plate when held next to each other, but it's there.
Personally, my stuff will never be that shiny (and I wouldn't want it to be). I'd lay strong money that the vast majority of vapers wouldn't notice a difference (and wouldn't care if they could/did notice)--but I have seen people dumping titanium accessories because they didn't match their stainless mods. Heck, I've seen people call out makers for using different grades of stainless on different parts of a mod because they polished up differently (and it turned out they were right--it was a mix of 304 and 316 stainless

).
If you can do titanium caps for the same price as stainless, it seems like a no-brainer to me to do it (I'd buy another set of caps just to save on the weight). I'm just suggesting you hold back a few of the stainless sets for the odd request from people who can see the difference (whether it's imaginary or not

)