I did a couple of shore dives this past weekend, and since the OP is close by me, figured I share some thoughts and experiences. The weekend before we went out on the Peace dive boat to Santa Cruz and Anacapa; conditions were OK but less that stellar, as in 25 to 40 ft viz. It was a whole day affair, on the boat before 6:30 AM, back at the dock around 7 PM after 3 dives. Some buddies and I decided to go out on Saturday at Leo Carrillo state beach, met around 9 AM, geared up, and had a nice 70 minute dive. We probably saw as much interesting stuff as on any boat dive the weekend before. Enjoyed showers at the beach to lightly rinse off salt, then each took off on our merry way around noon (I spent the afternoon running around doing errands). I've got an annual state parking pass, since I enjoy the state beaches, so the only out of pocket expense was the cost of an air fill, compared to $120/person for the dive boat.
Conditions for our beach dive were at least as good as we expected, so one buddy and I tentatively talked about another beach dive Sunday morning. The plan was for me to check out conditions and call him, with several different spots as potential dive sites. Conditions looked about the same, so we decided to meet up at 10 at Leo Carrillo for another dive. We got in another easy 70 minute dive, saw a lot more different critters (the highlight - 5 bat rays Sunday, compared to 4 octopus on Saturday), and were on our respective way a little after noon. Again, the only cost was an air fill (less gas than diving to a boat dive, so I'm not counting that) - and no worries about a wet fill from a dive boat. When I got home, I washed up dive gear and me, grabbed lunch, and still had time to go out and play golf with my wife
Was the shore diving this past weekend as good as a day on a boat? Probably not, and much more limited as far as possible dive spots, even though there are probably around 20 good shore dive spots nearby. Certainly much more affordable on a weekly basis compared to a dive boat. If I had friends visiting on vacation who wanted to dive a bunch, I'd probably take them out on one or two shore dives on days we had other activities planned, and the rest of the time we'd plan boat dives to experience the better spots and conditions, unless cost became a major deterrent
If you never do shore dives, it's intimidating, lots of work, and potentially problematic if there is much surf. When you go all the time, and have the right equipment and technique, it's generally as easy as diving from a boat in comparable conditions