Pact of the Chain is a fantastic scout
In a campaign now dormant, my Pact of the Chain Warlock, Archfey patroon, had a Sprite familiar.
The invisible scout was an immense boon to the entire party. It could fly and scout ahead of where we were going in all environments other than underwater. Sprites have bonuses to Perception(+3) and Stealth(+8). As we did not have a Rogue, nor a Bard, nor a Monk, my Warlock took on the scout role.
You could use an imp as well to be an invisible scout. (Per Zeiss Ikon's answer)
You ask if you are missing the point.
I answer that "good scouting prevents a lot of surprises and TPK's. Good scouting can also provide information to the party thanks to that little invisible spy listening to NPCs and Monsters, and the Warlock being privy to that information."
That seems to me to be a large part of "the point."
Another handy feature is that the familiar can offer you the help action (roll with advantage) for nearly any skill check (save lock picking and forcing open doors?). That's nice.
The pact choice may be campaign dependent, and party dependent
If you already have someone in your party who is a superlative scout, Pact of the Chain may not give you what you think that you need out of an arcane caster. In that case, pick a different pact.
I suggest to you the following before you reach third level.
Look at your party. How good is your party's scouting function?
If it is excellent, you may want to choose a different pact.
If it isn't excellent, Pact of the Chain gives your party a superb scout. And you still get to cast spells, etc.
At higher levels, there is an invocation that lets you cast hold monster without using a spell slot or needing material components:
Chains of Carceri
Prerequisite: 15th level, Pact of the Chain feature:
You can cast hold monster at will — targeting a celestial, fiend, or elemental —without expending a spell slot or material components. You must finish a long rest before you can use this invocation on the same creature again.
I have only seen this in play once, but when it worked (fiend failed the save) the held monster got slaughtered by the rest of the party.
As regards the gift of the ever living, its value will depend on how much healing your party, and your warlock, needs during an adventure day.