The difference is very small
Let's line up the options to see how they do compare:
Aspect |
Paladin |
Warlock |
Better |
Hit Die |
1d10 |
1d8 |
Paladin |
Spell Selection |
1 Spell |
2 Cantrips 2 Spells |
Warlock |
Spell Slots |
0* (5 Lay on Hands worth 1 level 1-2) |
1 level 1 |
(Warlock) |
Other |
1 ASI or Feat |
Fey Presence |
(Paladin) |
Lay on Hands for 5 points is worth a first or second level spell slot. It can heal 5 points of damage, comparable to a cure wounds on spell level one (5-8, depending on ability modifier), and it can cure a disease, comparable to a lesser restoration on spell level 2. The warlock spell slot may have more flexibility, but overall the value is not much different.
Fey Presence is a pretty powerful daily ability maybe comparable to a one time use of the fear spell, which would be a level 3 effect, and would be a strong feat, but a plain ASI can increase both your to hit and damage, a reusable effect, and is generally considered to be preferable to a feat. The ability to pick any feat also makes it a lot more flexible, so here I think the Paladin has the upper hand - for example taking a feat like Great Weapon Master can deal a lot of damage against lower-AC opponents.
Another way to look at this is to consider the situation if you picked the Magic Initiate feat with your ASI. This would give you one additional spell to cast per day, one additional known spell, and two cantrips, nearly making the score on both spell selection and slots even (the spell you gain would be limited to just the one spell, so less flexible than a full slot).
The remaining difference then would consist in one more hit point and the 5-point Lay on Hands with Paladin vs Fey Presence with Warlock. Mostly on the strength of Fey Presence and free spell selection with the slot, Warlock appears to be slightly better flexibilty and utility. However, the effective difference is very small. I think it would be overstating it to say the Warlock offers "far more" options and utility. It might offer slightly more.
If it does make sense to stick with Paladin or not will not depend on the mechanical difference here -- both are entirely viable. This will depend on your character concept, and on if you enjoy playing a paladin.