Does anybody agree with me that the demoman in tf2 is useless ? ?

i can see that the demoman is useless in face to face combat 'in an open location', his demos takes 1-2 seconds to explode while in 2 seconds you can run 3 steps away. lets suppose a heavy can't run that fast but his primary weapon is strong in nature.. i mean imagine u were a demoman and u were attack by a pyro .. isn't that painfull ??