I have 9 Qt for Android kits registered:
(would be cool if one could copy the list into the clipboard)
On each startup of Qt Creator, the QbsProjectManager plugin launches qbs.exe and qbs-config.exe 9 times per Android kit per architecture. That is the (2 * 9 * 9 * 2) = 324 first entries of the attached process monitor log: qbs_vs_androidkit_log.txt
This delays the appearance of Qt Creator for ~10 seconds. Turnung off the QbsProjectManager plugin reduces the startup time to a fraction in my case.