I see that as a plus to have a venomous spider along for the battle as he/she could jump off and land the coup de grace bite as a true battle buddy should.
I live pretty rural, tiny spiders/bugs/etc. love tiny spaces. I am not at all saying one will fall into/make a nest and you'll be kilt in da hallways, but it is something to consider.
I initially thought that then realized my intended use was indoors so little chance of occlusion. Went with a SRO and no regrets. Put the T2 on my pump which is used outdoors. No wrong answer as long as it fits the intended use.