There are a lot of times where tesserecting is superior to chasing on foot. I mean everything about conjurers is so circumstantial. Different servitor sets require truly drastically tactical decision making to be succesful.

There are certainly times where phase door is better then running by foot or tesserect as well.

My opinion also is that the tesserect spell is greatly underused by most conjies. It has so many different uses it is pretty amazing, especialy when you start using your familiar, gaunts, demons/angels and some of your detection spells to feed into knowing when to use it.