You can, for a while. Your assistant's own memory is built to remember you, not the two hundred people you deal with. It keeps a loose summary, decides for itself what to hold on to, and can't tell you what it matched or what it changed.
A spreadsheet holds facts, but someone has to keep the columns tidy, and the notes cell is where context goes to die. Two people called Sarah Chen, a job change, who introduced whom: a row can't hold that.
KnowWho is the structured book behind the conversation. Every person, company, meeting and promise is its own record, linked to the rest, and it tells you exactly what it saved.