Both Hexblade and Pact of the blade spend way too many resources just playing catch up to your basic Agonizing Eldritch Blast spammer. I know ther's some multiclass stuff you can do to make it more viable, but in general it just seems like its not worthwhile.
The main difference is just being melee versus ranged (hexblade can actually freely switch between both) at low levels-stuff like armor of agathys (which is honestly one of the best warlock spells) work much better in melee, and warlocks generally have several ways to get temp HP back, and with hexblade can kinduve effectively tank, even. Heck, very effectively tank if you go all in on it.
Regardless, it effectively lets a character do what it wants to, and while agonizing blast spammers might be more effective, there isn't anything wrong with blade builds.
