My dock already is too long. Not using SIri. Spotlight: still too much typing.
Math Notes is cool, but not really instant.
What is a "key chord"? Like a keyboard shortcut? Possible, but I work on multiple Macs of different eras and find that I use the wrong shortcuts on the wrong computers. Migration very nicely moved my F13 "delete file" shortcut to my new Mac.
I did find the Shortcut Maker - a pretty version of the old Automator (which was a pretty version of Older Scripts). So, created a Menu Icon. So, 2 clicks away.
As to PCalc, I'm trying not to add more apps until I've cleaned out the old, non-working ones inherited on this migration. I still have Snow Leopard apps that migration moved forward. On the other hand, it has to be better than the native calculator.
And, I really miss the widget dashboard. Still. Forever.