Vespid: Are they worth it?

With the rebuilding of my Cadre during the last few weeks I have found myself seriously thinking of deploying a few Vespids. I want to do this more because I have found many Tau Army Lists to be roughly similar, and by making use of a few Vespids I can give my Army List something unique.

But more importantly for me, having a Stingwing group will be something
of a surprise to my opponents.

The biggest problem, I believe, most Tau players have with the Vespid is their cost. Costing barely less than an Assault Marine, the Vespid have lower BS and WS, not to mention one less Strength, but most importantly, the Marines have an armour save of 3+ whilst the poor Vespid are stuck with a measly 5+.

But, I do honestly think Vespid have a place in any Tau Cadre. And I think Vespid will make most opponents wonder what you are actually planning on doing with them.

The Vespid are fast, very fast, and mobile, even by Crisis Suit standards. This I find very appealing, being able to move 12 inches, and able to re-roll failed Dangerous Terrain is something that I find particularly appealing. It also gives a hint where the Vespid should be. Vespid should never stray far from the cover save that will be granted by broken terrain. A 4+ Cover Save is going to increase their life span on the Battlefield by quite a bit.

The Vespid differ from Kroot in that they are too expensive to be used as a simple roadblock to protect Crisis Suits and Broadsides. I would used them as a rapid flanking force, circling round to engage long range units such as Devastators.
The low BS of Vespids could be hindrance here, but with the use of Pathfinders and Markerlights I think the Vespid can be very effective. The Neutron Blasters with their S5 AP3 can be very useful, negating the Marine armour save.

Furthermore, I don't think one should be too afraid to Assault with Vespid. Bearing in mind it is better to first thin the ranks a bit, Assaulting can be a useful tool to finish off small groups of Space Marines, and more than anything else, it can a big surprise to have a Tau player Assaulting.