Sometimes simply being programmable is enough, you don't need all that much speed.
SeRV at 60 kHz is going to do between 1000 and 2000 instructions per second, depending on the instruction mix.
As something to compare that against, an Apple ][ running AppleSoft BASIC runs `FOR I=0 TO N:T=T+I:NEXT I` at 250 loops per second.
On SeRV that loop is going to be something like ...
loop:
add a1,a1,a2
addi a2,a2,1
bge a0,a2,loop
... which will take 96 clock cycles per iteration, or about 600 loops per second at 60 kHz, so that's 2.4x faster than AppleSoft on an Apple ][. Which many people found fast enough to start a revolution.
Yes, AppleSoft is using floating point numbers, which are slower than integers, but Integer BASIC only runs that same code at about 330 loops per second.
Original IBM Model 5050 PC runs the same loop at 415 loops per second in BASIC (380 for BASICA), if that's your reference ecosystem. Not a big difference. Still slower than SeRV at 60 KHz.
Oops, sorry, that RISC-V code will be 128 cycles per loop on SeRV not 96, as the branch needs 64 cycles. So about 470 loops per second not 600 on that flexible chip.
Of course this doesn't alter the point about being as fast as the BASIC that early PCs came with, the only thing most end users had to write their own programs on them until things such as Turbo Pascal appeared (November 1983).