Well, SPEE(and many more E's)EED won't help you to deal with the defenses at a tipped military settlement
And while landed, speed is useless - but defenses (shields and hulls) are not. What i mean is having strong defenses will buy you enough time to get out of that building and defend your ship if you get a drop of scavs while you are busy inside.
Defenses on settlement and scavs aren't a big deal for me, since I'm not green enough for these mistakes anymore xD
First order of business on settlements where I didn't get shot before landing is always to check the Contacts tab. If I see targets, then it's either wait to kill on sight, or just send the ship away and hunt. And if they drop late, sending the ship away is always easy to do on the fly (you don't NEED to wave to your ship to dismiss it, as fun as it is to do this way).
Even on rare occasions when alarms go off, ship only gets shot after leaving the landing pad, so that's not an issue since you can just disable defenses (it's on the way 90% of the time, so making a mistake and getting alarms off is even less of a problem).
Only situation when defenses actually interfere is when it's a massacre and you get tipped off, which is only one variation of one mission type, so not common at all. If I'm mixing a lot of missions with one or two massacres and I get tipped off, it's still easy to go around it. If you have other mission on the same planet, do the non-tipped off first, call an Apex to the tipped off, get dropped off without problems, and do as normal (everyone is red, and will hear your footsteps, but that's no factor against Silent Footsteps, which helps on every other mission). After mission is over, recall the ship (bit of a trek, can be skipped with a nice & dirty relog, but it's not a big deal to walk). Otherwise, just use Apex after prior mission to the tipped off, and recall the ship via Inter Astra when back at station. On cases where there is more massacres that can be tipped off than otherwise, I just use Apex out of the station and grab a drink, since I'm not driving.
I personally see no reason to do on-foot content from inside the safety of an SRV or ship, and I love the way things are balanced and designed in a way where any solution to these problems is possible and easy, regardless if you're only going on-foot or not. That's why it's important to go with what is fun, since with skill and knowledge the amount of optimal solutions is larger than we think.
Would still pay credits to not get tipped off, but it's the kind of spice that shake things up.