If you're asking for a personal preference, then "no" I don't use the "pin to start" option if an app doesn't work properly. Normally, I would reinstall the app, restart my phone or perform a soft reset (- won't erase your phone data). That also happens to be the generic solution to those types of problems in addition to making sure that your phone isn't in Battery Saver mode (when the charge is below 20%) and that you have good Mobile data coverage.
The "App Gap" doesn't exactly refer to the defects and flaws of certain apps. Rather, it refers to the absence of official apps in Windows Phone that are present in other platforms such that there is a "gap" in the number of official and available "apps" in Windows.
The "Pin to Start" option is for the app, usually not from a web site.