Contrary to common belief (in the modernist mindset of 21st century America) that black doctoral gown that a Baptist, Methodist, or Presbyterian preacher wears is not a vestment. It is an academic gown and a means to display his educational credentials to preach and teach. The use of the academic gown by clergy developed in the reformed churches upon the rejection of the use of vestments. In much of the Anglican tradition the common Eucharistic Vestments (Chasuble, Stole, Maniple, Alb, and Amice) were suppressed as being papist superstition while the Surplice and Cope were retained. Because these are not Mass Vestments to which specific superstition was attached Anglicans did not see the need to suppress their use. The Surplice, worn with the cassock, tippet, and academic hood became essentially the norm as far as vestments go in the Anglican use. On the other hand the more reformed (Calvinist, Puritan, Zwinglian) christians all together reject the use of vestments. Instead of vesting these traditions used the academic gown as the ministerial wear of clergy.
As I stated above, the stole is a proper vestment and in particular it is a mass vestment. It represents the yoke of service to God. The academic gown is the symbol of the very rejection of vestments. To combine the two a theological oxymoron.