She ain't just setting him up in a cosy cottage with a garden and care staff - she's giving him access to top secret UNIT history! He's getting all the dirt on the Doctor, Liz, Jo, Benton etc from the 70s/80s! He's getting to see all the alien artifacts collected over the years! Kate is going round there for tea and a chat every Sunday, sharing stories her dad used to tell her and updating him on what the Doctor is up to and Wilf's eyes are sparkling every time while trying not to cry because he can't have these chats with his granddaughter.
the convoluted doctor who lore gets extra funny when you realize that, at two separate points in the past, two different companions to two different doctors ended up running into rasputin but both came to the conclusion that he was a pretty nice and normal guy. which, depending on how you interpret the power of the doctor, is either a nice subversion of a lot of tropes of stories used in pre-soviet russia, or side-splittingly hilarious as you start imagining the master getting roped into various adventures with different versions of the doctor that he can’t fuck with yet or else he’ll destroy the timeline, forcing him to play nice with the humans as part of his 4D Time Chess Master Disguise Plan #3852